Many of them are staying at their parents still.
Having said that I may be completely off base here since I do not know Japanese culture well enough.
On hacker news since most people are in CS/IT, a field that is almost free (but not for long), it may look like we still live under goverments that are business friendly. But that's not the case at all in other sectors, and many people aten't allowed to find a place in the market.
People today can't get their feet wet when trying to find a place in the market, they must immediately do a full dive. No wonder more and more are drowning.