in all seriousness there is no backup beyond a few hundred beds in even the largest cities, with waiting lists, and not exactly the first thing you think of when things turn strange in your life and you end up on the street suddenly. You don't think that you are "one of them" and you just are "holding on for this or that" to happen. At some point, if you exit early enough, you can still transition to other societal levels. Left long enough, it changes you or at least you are considered differently and looked at funnily, to say nothing about the difficult in maintaining work and income to get OUT of said situation, etc.
There's probably some better and worse areas in a city for pitching a lot of tents for a long time. For example some unused parking lots could work better than streets. It would make sense for the city to provide some basic services there too, like water, toilets and a trash skiff... probably some person actually doing it would know a lot better what's important, and what would be alleviate the need to camp somewhere that causes problems for others.
It seems that there's this discussion between false alternatives like "let people do anything" and "let's punish people harshly for minor things". How about offering better alternatives, giving people instructions first before any worse consequences etc.