I live near Boston. Part of the housing supply issue here is the mandate for a certain amount of “affordable housing” in all new developments (I forget the percentage, on the order of 10-20% of new units?). This results in either housing not being built, since the developer would not be able to earn enough on the sale of the building due to below-market rent payments, or the non-“affordable housing” units have to pay above-market rates to subsidize/offset the below-market-rate units.

This drives me nuts, because the goal should be for 100% of housing to be affordable. Stifling development or shifting the unaffordability to different areas of the income distribution do not solve the problem. More housing has to get built. This is a supply-demand issue, as anyone with basic economic knowledge can tell you. There are two ways out: people relocate, or more housing gets built.