Tech millionaire builds 99-unit tiny house neighborhood for homeless Canadians - rent is kept at 30% of income, the large majority of residents pay a maximum of $200 — including all utilities
This could be pointed to as a successful test case to get the gov off it's ass and implement this at a macro level.
You are correct millionaires will not save us, however we should reward behavior we want to see. Lest we get more billionaires who are a net drag on society.
How though. Anti taxers would point out that it should be an 8 story concrete apartment building for maximum return of government investment, but no increase in taxes, any concerned official is left fighting politically for leftover funds to slowly build up in an account to initiate the project, and then they loose an election and the next guy uses it on fancy jewlery for his mistress.
Even just getting one building off the ground and they’ll be eviscerated for not using economies of scale. Building ten at the same time and a slight cost overrun which always happens is multiplied by ten.
Maybe if they all teamed up and were organized to do so. But a tiny handful of billionaires control as much wealth as the millionaires. It's much harder for a class to voluntarily do good than for a small handful of people. That's why society needs to step in, tax them, and distribute to projects as needed.