When salaries are high enough, more people can invest in building more housing. So as landlords drive up the prices, the market balances.

But since the wealth gap keeps widening, fewer and fewer workers can afford this, as they get priced out of locations that offer good employment. At the same time the rich keep investing their money into higher-margin industries. Consider that for landlords owning enough housing, building more can have a negative RoI, and they all know that they all know this!

If you don't believe me, think about just how quickly the datacenter boom became reality. All that money was waiting around, and evidently could have been turned into a lot of building activity in a short amount of time.