The bigger problem, at least in my neck of the woods, is they're not building affordable housing. By-and-large they are building luxury apartments and luxury homes. We've torn down half the city to build luxury apartments that sit at 20-30% occupancy. Building luxury housing won't help the housing crisis until the sellers are on the brink of bankruptcy and forced to sell their properties at a reasonable price.
Asking why they don't build affordable housing is like asking why don't they build used cars
Your argument falls apart when you realize they manufacture and sell explicitly affordable cars. It's nearly half the market.