Tokyo is also well known for needing to pay to be practically anywhere except public parks which are relatively few. Yet the homelessness problem is near nonexistent. I don’t think this is the reason either, though it doesn’t hurt to have.
Look Americans just hate it when poor people get things for free. Despite the fact that the US economy can afford it- certainly better than the Japanese economy nowadays.
It is perversely CHEAPER to give someone a flat and 1000 eurodollars per month than to have them roam the street, using drugs and being a nuisance.
This is the wisdom that all first world countries have learned. Pay people money to shut the fuck up. The bread and games of the Romans.