Same in London. You see large groups of them under bridges sometimes, but then a few days later they're all rounded up and just gone. I'd like to believe that they're under Shelter protection, but the cynic in me k ows that they've just been relocated out of the public eye.

>Can homeless Japanese set up a tent on a sidewalk in the heart of Tokyo?

I don't know, but I seriously doubt it.

I generally only see them in certain public parks. There's one weird encampment in some woods next to one of the rivers, in a large park that's on a flood plain; not exactly easy to find or heavily trafficked.

>Can homeless Japanese set up a tent on a sidewalk in the heart of Tokyo?

Yes. I encountered a homeless person in the CBD of Tokyo, sleeping in the bushes of a (very small) divider between a main road. Almost totally hidden, by those bushes. With enough items to look like they'd been there a while.

To be honest, I don't know much about homelessness in Japan besides what little I've read online, and what I actually see in public (and considering how much I walk around different places, I do see a lot of places). Anyway, I suspect this is probably another case where America spends a ton of money on stuff, but does so poorly and with bad effect. Just look at healthcare: the US spends far more per person than any other country, but outcomes are pretty lousy on average because it's so unequal and because treatment costs a fortune compared to anyplace else. I'm sure many other spending comparisons between the US and other nations are similar. How much money has the US spent on high-speed rail in California without getting much done?

I don't know what your point is, but the USA also spends tenfold on infrastructure per km with vastly worse results, and has the highest spend on healthcare per capita, with one of the worst outcomes in the developed world. So just spending more doesn't mean much.