It's similar to how they developed their high speed trains. The government did the basic research and development, and then it grew into a huge business where Japan lead the world for over 50 years.
Interestingly that's the exact opposite to the way the UK works. You see we put in all the risky research money to develop tilting trains. Then because "reasons"[1] it was shut down and sold off and we're now buying tilting trains from Pendolino (a foreign company which bought the rights cheap) at great expense. The original tilting train still holds the speed record on the relevant routes.
Which is a better investment, I shall leave as an exercise to the reader.
[1]The reasons were bogus. Some people claimed it made people feel ill. There was an early problem because the tilting compensation was too good. Dialling it back a bit solved the problem and the trains became no worse than the modern ones in that regard. Basically the reason is that no matter who is in power, parliament hates local industry for some reason.