But let's assume the whole thing is a money blackbox, you must realize you cannot output that much good from the little change "build build build" without inputting
something.
This something, the tax rate increase, or any other way to finance this whole operation like an increase in loan risk by large builders, would probably be phenomenal enough to make it completely off putting to most workers. People are not rational long term altruist thinkers: they want the best deal possible, and it's not to make SF more affordable in 30 years by over financing house construction today before they finally die of proud exhaustion like "I contributed to cheap rents for my descendants".
I prefer natural selection: you talked of Paris, the city is half stable now. It's always been the hyper center of France, we've always had higher inflow than outflow, prices have raised slowly every year since 1800 at a higher pace than wages, and now it's going down. We're developing stuff elsewhere, not only the outskirt but other part of France entirely that people would dream to move to after a stay in Paris.
The alternative you propose is to build the city I live in now: Hong Kong. Here, since we can't escape anywhere, all we can do is build build build. Our long inflow of desperate Chinese has made construction efficient, fast and cheap enough. Price are more commensurate with wages than Paris, even if they can appear absurd to the poor people in America. But, do you want to live like me in a small 2-room flat on the 44th floor of a giant tower surrounded by other towers ? That's the future you propose, eventually. Lots of homes in the single most important city, the dream !
I like the alternative: to just jump elsewhere and start over. Let the people starve due to mortgages in California and build a new hub in Ohio or whatever, they'll figure it out eventually.