As Bloomberg forefronts in "Why Half a Million Young Japanese Can't Face School or Work" — before admitting in the 4th paragraph that the issue — the "hikikomori" — is not new.
The current issue is that the Japanese Prime Minister, Shinzo Abe, sees this matter of life-style choice and psychological orientation as problem in need of government intervention because the population is dropping. That is, the nation needs these solitude-loving people to have babies. But, it seems (it's hard to read through the dross in this article) the government is funding this stay-at-home behavior with welfare.
The article puzzles over why young people are doing this. Were they bullied at school? Pressured by parents? But what's so hard to understand? People respond to government incentives. If you had told me when I was 20 that I could stay home, not work, and receive monthly payments to cover basic expenses, I'd have snapped up that deal with pleasure. I can stay out of the workplace and use my time however I want, free from economic need? Sign me up!
Now, maybe you'll tell me I don't understand hikikomori and that these are people who feel strongly reluctant to get out into the world of work. But if you'd given me that offer and I'd gotten set in my ways of collecting a monthly check while I stayed home in my safe, comfortable apartment and read books, drew pictures, and listened to music, and then you threatened to take it away unless I manifested anxiety about going to work and supporting myself, I'd have the requisite anxiety.