[mseebach]

> people don't get "sticky"

People would get VERY sticky against moving away from a subsidised area, even if it might actually suit them better, and they could afford it - leading to sub-par allocation of resources.

Also, there's the question of how/when/if to pull back the subsidy. If you do it according to income, you create a very high marginal tax rate at the beginning of the pay scale - that's toxic to work and traps people in poverty. If you do it when the children are grown, you're suddenly kicking people of of family houses they've lived in for decades (see "Bedroom tax" in the UK). If you don't, then what started as a family neighbourhood becomes a neighbourhood of middle-agers living in large apartments - while their kids struggle to find a decent place to live.

Incentives are HARD.