> You build as much new housing as you can afford to, and let older housing filter down to "affordable" levels.
In many larger cities, older housing occupy prime location where the value of the land is twice the value of a new building you could build on it, so all these would never filter down to affordable levels.
In many larger cities, older housing occupy prime location where the value of the land is twice the value of a new building you could build on it, so all these would never filter down to affordable levels.