[Symmetry]

As long as new people keep being born, they're going to have to live somewhere. You can choose the Greenwich Village route which SF seems to be doing and maintain the outward appearance of the place at the cost of that place becoming ever more exclusive, or you allow as much new development as there's demand for and the place starts looking different but doesn't become any more exclusive. It's worth emphasizing that this doesn't have anything to do with Capitalism. In a command economy you'd see the same thing with the powerful using their influence to get slots in the city, and the same sort of outflow of existing residents.

Maybe if SF succeeded from the US and California and ran a tight immigration policy you could make stasis work, but somehow I don't think that's in the cards.