It now costs ~427k/apt to build in SF.

https://www.spur.org/news/2018-05-09/it-all-adds-growing-cos...

I'm not sure what the rule of thumb is for commercial builders, but for real estate investors, a good deal is that 1 months rent = 1% of the price. So.. yeah, I dunno if there's actually that much wiggle room.

It may work if it's a nation-wide policy. But let's say you enact this policy in one city and I'm an investor. What's to stop me from just deploying my capital elsewhere?