Japan is a harsh society in some ways. These people were pushed into homelessness by the economic situation in the country combined with the high cost of living. Japanese aren't very forgiving about debt so some of those people in the park were former business owners who accrued a large level of debt that would be difficult to repay. So their choice is between slaving away to repay that debt and living in the park. I'm sure some may be choosing to do both. Renting a tiny apartment (and I do mean tiny) is especially expensive in the metro areas where most of Japan's population lives (and you don't find good jobs outside that metro area, that's a whole issue unto itself). another really old thread I dug up: Is the USA heading the way of Japan?
child poverty and soup kitchens for single mother families: https://www.theguardian.com/world/2...-truth-behind-two-decades-of-economic-decline
Homeless people in Japan are mostly former seasonal labourers who are now too old or sick to work at construction sites. Their situation is quite similar to menial workers from Mexico who work illegally in America and there is no social safety net for them in Japanese society. At certain places in Osaka, there are spots for these seasonal workers to get a day job and they are transported to construction sites. The younger, the better, and they have no choice but to sleep rough when these jobs dry up because of their old age.
I was in Japan in 1954. I won't forget the wounded that survived WW2 being on the sidewalks begging and selling pencils.