Exclusionary zoning benefit those that own housing the most, so it does benefit a bunch of baby boomers. However, those with leverage of existing rental units seem to benefit the most because they gain leverage through rental income in the same market as they buy new units in so they can slowly gain new low-risk wealth over time without changing their cost/revenue balance.

In general low-risk investments such as student loan bonds and rental properties should be low-margin. However, due to regulations that stop the market from doing its thing that is not the case.