A success in Japan involves only the 1/70 of the world's populations. With a typical ambition of bigger successes in business, I've tripped to several major cities overseas; Silicon Valley, Bangalore India, Berlin German.

There, I was surprised to see how little noticeable Japanese companies were round the worlds. Their presences were seemed a bit stronger back in 2005.

So, I gave myself time to think thoroughly about these two questions without relying on any kind of media, texts and other resources.
1. Why a small island country like Japan without any major resources were able to gain such a strong economic growth throughout the world in 1980's?
2. Why have they grown so weak today?

In 1970's and 80's, the major Japanese companies such as Toyota, Sony, and, Honda with non-English speaking leaders, rapidly, swallowed the world's markets. Overwhelmed by their strong presences, a protesting movement against Japanese occurred in both USA, and Europe. So, I have read though I wasn't born yet.

Japan bashing; The political, and economical attacks toward Japan which occurred in Europe, and USA. It’s introduced in Japanese school books with the pictures of people smashing Japanese products with some hammers.
The World Market Capitalization Rankings in 70's, and 80's, discussed frequently on SNS may indicates how powerful, strong the Japanese companies were back then roughly though it doesn't tell us everything.

★World Market Capitalization Rankings 1988
★World Market Capitalization Rankings 2018
The whole charts of 1988 & 2018 attached at the end.

World Market Capitalization Rankings 1988
No.01:NTT(Nippon Telegraph and Telephone Corporation) (Japan)
No.02:IBJ(The Industrial Bank of Japan, Limited) (Japan)
No.04:FBK(The Fuji Bank, Limited) (Japan)
No.05:DKB(The Dai-Ichi Kangyo Bank, Ltd.) (Japan)
No.06:IBM(International Business Machines Corporation) (U.S.A.)
No.07:The Mitsubishi Bank, Ltd. (Japan)
No.08:Exxon Corporation (U.K.)
No.09:Tokyo Electric Power Company Holdings, Incorporated (Japan)
No.10:Royal Dutch Shell plc (U.K.)

NTT as the top company?? How did that happen? Could somebody explain what made Kansai Electric Power Co., Inc. (KEPCO) ranked in 21 place? Wonder why.

After World War Ⅱ ended with the atomic attacks in 1945, Japanese before us rebuilt the society from a scratch. The remarkable progresses they’ve made including the strong economies in 40 years is unreal. They are now over 65-year old or elder. I have nothing but a total respect toward their power to revive.
Off the topic, but some Japanese TV programs, and economical experts claim that Japanese economy is slowing down because those senior generation owning most of the domestic wealth is holding back their money.
But, let me just say that they are the ones that made a great deal of effort to earn the fortunes. They have the right to whatever they want with their money. We, younger generations, on the other hand, haven't done much, but just being lucky to be born in Japan they rebuilt at this era, and depending on the older generation for our economy makes no sense! Just a personal point of view that is.

Anyway, here is World Market Capitalization Rankings 2018
No.01:Apple Inc. (U.S.A.)
No.02:Amazon Inc. (U.S.A)
No.03:Alphabet Inc. (U.S.A.) *a holding company of GOOGLE
No.04:Microsoft Corporation (U.S.A.)
No.06:Berkshire Hathaway Inc. (U.S.A.)
No.07:Alibaba Group Holding Limited (China)
No.08:Tencent (China)
No.09:JPMorgan Chase & Co. (U.S.A.)
No.10:Exxon Mobil Corporation (U.S.A.)
The whole charts of 1988 & 2018 attached at the end.

Not a single Japanese company listed within the top 10! Just 1 name to be found in the top 50; 2 % in upper half, the only company would be TOYOTA! in the place 35th. Thank you! TOYOTA! Still, being in this place in the list is praiseworthy of course.

There will be no ''Japan Bashing'' anymore! An expression like ''Japan Passing'' not considering about Japan at all, may take its place. How
about 'Japan Nothing' in the end? Now, that's hard!

A personal conclusion to the first question:
1. Why a small island country like Japan without any major resources were able to gain such a strong economic growth throughout the world in 1980's?

That's because the craftsmanship, and the manufacturing industries were the most demanding field of business in 70's and 80's. Following the ending of the war, the social infrastructures were reconstructed, and enhanced more than ever. Such as TV-sets, washing machines, fridges became a standard equipment in a household across the world. People were attracted to new electronic machineries, and products.
There, the characteristics of Japanese in general best matched with the world's demands for the products with high-qualities, and, accuracy.

[Favorable tendencies of Japanese for product manufacturing]
✔️ They were good in hand crafting in general
✔️ Follows the schedules and meets the delivery deadline
✔️ Makes never-ending efforts for improvements, cost reductions on products; motivated by a sense of honorable poverty, and virtues.
✔️ Hard-workers in general, no need for a watchman.
✔️High performances in group actions when commanded: suited for manufacturing operations.

These elements may also had encouraged the strong comeback of this nation 30 years ago.
✔️Numbers of armories abandoned from World-War2 were reused as manufacturing factories.
✔️There was a reduction of national defense spending under the protection by USA over Japan.
✔️ The enormous energy focused on the war, and the frustration of losing it was, then, poured into the manufacturing, and the improvement of economy.

In any cases, Japan did become the world's factories for manufacturing, and the phrase 'Made in Japan'’ represented the high precision, and fineness of products.
Simply, Japanese were best suited for the manufacturing industries.

Moreover, the language barrier wasn't much of a problem for Japanese in 1980's. it wasn't required if the qualities of the products were assured. A poor language skill of workers including CEOs however, could become a bottleneck for a company like ''Bell Face'' providing a SaaS style service.
Reinforced by a great deal of investments, Japanese made their companies on the top of the capitalization rankings 30 years ago making the banks profited in return.
This is how I think the Japanese made it to the top.

Now, it's the second question; 2. Why have they grown so weak today?
It's because the platform business is the most demanded field today.
Definition for a platform:
ttps://en.wikipedia.org/wiki/Platform_economy

Reviewing the World Market Capitalization Rankings 2018, It's obvious that the most of top-ranked companies are Platform based.

Platform Based Company: (P)
No.01:Apple Inc. (U.S.A.) (P)
No.02:Amazon.com, Inc. (U.S.A) (P)
No.03:Alphabet Inc. (U.S.A.) *a holding company of GOOGLE (P)
No.04:Microsoft Corporation (U.S.A.) (P)
No.05:Facebook, Inc. (U.S.A.) (P)
No.06:Berkshire Hathaway Inc. (U.S.A.)
No.07:Alibaba Group Holding Limited (China) (P)
No.08:Tencent (China)
No.09:JPMorgan Chase & Co. (U.S.A.) (P)
No.10:Exxon Mobil Corporation (U.S.A.)

The potential of platform business is too-well-known already. But the point I ought to make here is that the Japanese are not fit for the platform type operations. A platform-based business could be a vast extension of network that takes everything in, transferring them into simple components of the network itself. Japanese will struggle over a marketing strategy like this. Simply, because they mainly, specialize in manufacturing. Let me put it this way; if japan-made product is ''a dot'', the vast network is a plane that observes the ''dot'' in as part of its’ body. Although, TOYOTA had spread the concept of ''KAIZEN'' throughout the world, ''Platform'' isn't about a product, it's the network system that counts.

And, this is where Americans come in. It’s needless to say that USA consists of varieties of emigrants from all over the world in the first place. Handling diversities of products, and services to refine the value of the platform is like second nature to them.
In addition, they have less frustration over communication. Imagine if 3 billion people on earth spoke Japanese as common language. Sure, Japanese would develop global business! This is the kind of world Americans are looking at.

Japanese are still very sufficient in manufacturing, but the qualities of products isn't enough to win the competition. Platform is the key.

Here is an example of Japanese being unable to catch up with the change. Sony was said to had developed some products similar to iPod of Apple but failed to have a platform-based strategy like iTunes application which allows users an easy access to vast variations of music.

Sony, also, attempted to get a chance by developing an E-book reading device similar to Amazon's Kindle. But failed to enhance the devices with a system like Kindle book contents of Amazon; a platform-type services providing vast choices of books. Sony, again, loses an opportunity to be the leading company.

In another word, it's no use aiming for Japan's strong come-back in manufacture industries in the new era. There is no chance for Japanese to get anywhere as long as we keep repeating the cycle of 1: Focusing, only, on products’ qualities → 2: Have the technologies brought out to abroad by some other, or some platform companies may, simply, buy out the resources.
Moreover, we should keep in our mind that Chinese manufacturing levels are improving.

TOYOTA is still maintaining the name, and qualities, but it won't be long before they, too become nothing more than a huge storehouse for those platformers like Apple, and Google.

The world is already shifting from ''possessing'' to ''sharing'' in the first place, and the change is occurring much quicker then we think.

Tesla Motor led by Elon Reeve Musk, a man I admire, has already realized the remote software updates of the vehicle.

An electric car consists of a fewer parts compared to that a gasoline car. Not being unable to make shift to electric car, TOYOTA now, faces a difficult phase of its survival. There may not be a place for them even in their home grand: the manufacturing industries, in years ahead.

10 years from now, the name of this company may not appear within the top 50 of the global capitalization ranking.

Summary

1. Why Japanese companies in 1980's gained the strength to be the top-ranked companies in the world?

That's because the craftsmanship, and the manufacturing industries were the most demanding field of business in 70's and 80's.

2. Why are their presences in the global market has grown so weak today?
It's because the platform business is the most demanded field today.

I have to say it's just the change in the times we can't fight against. There are little chances of Japan regaining an economic growth in the next few decades.

The current Japanese political state makes the situation even worse.
Though it's depressing to face, this is the reality ahead of us.

The country of Japan will, quietly, fall enclosing it's beauty inside. It's safe, and, comfortable environment with the spirits of hospitality is best matched for a world-class resorts’ developments.

However, this is a path the nation of Japan as a whole, would take. It won't, necessarily, apply to individual business scenes.

Who knows! some exceptional Japanese venture with a whole different level may arise, and become a global company like Amazon, and Google one day.

The world has proven that a single company can entirely, change the image, and the presence of a country.

I'm learning English thinking that why can we be the ones to be the next global influencers. No reasons to deny the possibilities.