Look at the culture and the accomplishments of a place like Rakuten, and plot a way forward from that to a tech powerhouse. I don't see it.
Japan obviously can find a use for software developers. Japan launches spacecraft, has 2 of the 3 major video game console companies, is well-known as a major place for robotics, has major car companies, and has started to get back into military equipment.
Programming isn't all about web sites and phone apps.
To suppose that Tokyo can go in one direction or stagnate while the rest of the country goes in another direction and prospers is just totally unrealistic.
And Rakuten does a lot of stuff. There are also places like GMO that do things. This is kind of like complaining that Ebay isn't a tech powerhouse. That's totally fine
It's just difficult to imagine how a world-class tech company can rise up from Japanese business culture, at least on time scales that don't span decades. (For me, anyway, YMMV I guess.)
Japan is the source of the world's most popular operating system, iTRON. Never heard of iTRON? Ah, well, it's probably in your microwave or anti-lock brakes or thermostat or coffeemaker or ...
I have to say that the horrendous UI of Japanese consumer electronics in the 1980's and 90's seems quite closely linked to Japan's slide from the top of that market.
Seven years ago, when I first visited Japan, everyone used a clamshell phone with a godawful LCD interface. Today, everyone has an iPhone or iPhone clone (aka Korean or Chinese Android device). Even today, mobile carriers usually have a "Japanese Only" section on their website for the nationalists who insist on buying Japanese, and, sadly, those phones are very underwhelming by any reasonable standard in 2016.
To me the average level of developers at most companies I know is just heart-breaking, many times they don't seem to be thinking on the right abstraction levels and instead treat development as something you just persevere through by pure exercise of will (which is of course exactly what you are rewarded for: put in long hours, results don't actually matter as long as you try your best, onboarding/training is limited to manners, how to clean the whiteboard and how to water the plants (not joking), your university education/diploma is considered worthless, hence why lots of people suddenly become "software engineers" with a law degree or a biology degree or an english major degree because tech jobs generally pay better). In the end in my opinion the prevalent culture/values are just not very conducive to becoming better at software (although it kind of works in hardware and on the outside definitely appears to work in services).
I'm torn on the utility of it; unless you're actively working in it the information degrades very quickly. And unlike spoken languages, if you try to come back to it later very little of what you learned before is still valid.
Classes on general computing - and not "coding" - would seem far more useful than teaching kids Python 2.x for a few years. But at the same time those would be far less accessible.
Spoken languages do change but you may only notice when you're already in your 70s.
I guess the Fortran programmers from 1960 might be at least somewhat familiar with Fortran 2008, but I suspect the gulf would be wider than a spoken language change. If I watch an episode of the honeymooners, the parts I don't understand are cultural, not linguistic.