>Not sure it's true universally.

I'm pretty sure it is, due to basic economics. Running shelters is not free. No one builds extra capacity that they don't expect to use. Assuming a reasonably efficient "market", new beds would get added only when there is sufficient demand to fill them. That means that there must be people without beds in order for new ones to get funded.

Also, I've never heard of anywhere with a significant population of homeless people that didn't have problems with shelter capacity. London alone has ~3500 people sleeping on the street each night. Are there really 3500 unused shelter beds in London?

http://www.crisis.org.uk/pages/rough-sleeping.html

Undoubtedly some areas do a better job than others, though.

> I'm pretty sure it is, due to basic economics...

Not being funny, but basic economics also rules out a bunch of other stuff that exists. For example, in Medicine Hat, Canada, they just provide you with an actual home of your own if you're in a shelter for 10 days.

Basic economics make that really expensive, but not just a waste of money, which is what excess capacity in shelters is. And yes, it's possible that there are places with tons of excess capacity because the people there have chosen to intentionally overfund out of an abundance of caution and compassion, but I've never heard of such a place.

> Basic economics make that really expensive, but not just a waste of money, which is what excess capacity in shelters is.

If you boil it down to a bed counting problem you're right, but it's not as simple as that. Take London as an example. There are shelters, hostels, and even B&Bs in use to keep homeless folks off the street. Each serves different markets, with seasonal changes. Empty beds are already part of the operating model for hostels and B&Bs, so the capacity exists. In my opinion the more challenging questions are around how to connect the supply and demand (in the presence of funding, obviously).

I'm not saying basic economics isn't a useful tool, just that it's usually a poor proof of anything in the real world. The clue is in the word "basic".