Like everything to do with housing in CA, this idea is ruined by Prop 13. If San Francisco's property tax collections had been allowed to rise with property taxes, their tax revenue would naturally rise as land values rose and they would be able to afford land no matter how high the land values got. However Prop 13 stops their tax revenue from rising as fast as land values so land becomes increasingly unaffordable to them as land values rise.

There's plenty of cheap land and labor 100 miles east of San Francisco. Why don't we build homelessville there?

Because nobody wants to live there? That's why it's cheap.

I fear a lot of SF homeless enjoy being in SF for similar reasons that a lot of the not-homeless do. Can the prospect of free housing in a random area lure them away? Maybe? It's hard to say.

Overheard a homeless guy in Mountain View, think he had a tent in one of the creek beds, saying why he likes it here: - ”it's safe, you don't get robbed". Less risk of violent crime in a prosperous, liberal city like MV, where the police management know they're expected to roll a car for reports of homeless-on-homeless violence, and can easily afford to do so.