> I never see the NIMBY movement really engage with what falling prices would mean in practice

It means the landed gentry lose, and the working class win. Unlike the status quo of the past few decades where the landed gentry make fistfuls of cash by doing 0 actual work.

Obviously housing prices going down will make some people's assets mixes worth less. That's why they fight to stop building housing. But that's true for lots of commodities and businesses too. Just because many people are invested in diamonds doesn't mean we have to ban lab grown to save diamond prices