People defile them, use them for shelters, or drug ingestion stations. There's no innovative way to solve homelessness. It's an insidious problem that defies any method to redress. Any angle you try to approach it from will be abused or defeated in some way.
Well, you can either have human rights (non-authoritarian states who won't use the police to crack down on this behaviour) or clean public toilets. Of course Singapore for instance has the cleanest public toilets, but you can also pay a 2k fine for chewing gum.
What happened to all the public toilets in US/UK? I remember there being many more, am I hallucinating this?
Many 2nd world countries still have them, for good reason!