Units built after 1980 in SF units aren't subject to rent control. On a purely econ 101 level "old units are unprofitable/new units are profitable" should spur more new construction to minimize the effects of old units on your portfolio.
I agree with this, but the misunderstanding because no one is explicitly talking about how there is a desire to preserve rent controlled units. This means it's very hard for the econ 101 to play out.