I'm pessimistic that this will happen any time soon in Japan, or any other country in the Far East, or pretty much every country except a select few. That kind of innovation is almost universally looked down upon in those cultures. You're supposed to be employed in a large corporation that makes tangible goods, not sit in front of a screen and churn out intellectual property.
Yes, they would love to make a billion dollars, too. But no, the sight of a bunch of college-dropout geeks doing what American startups typically do would be abhorrent enough to drive all investors a thousand kilometers away. You would be a shame to everyone around you. Your parents will not know how to explain themselves to their neighbors. Your high school teachers will deny that they ever taught you.
I seriously hope that somebody somewhere will say "F U" to all of that and just build something. Don't even target people in the same country, just sell it directly to everyone around the world. But even then, the sight of you straddling your MacBook in T-shirts and underpants like a hikikomori would be considered a shame to everyone around you. At least until you buy a sports car with your hard-earned foreign currency.