I'm not arguing that urban density is less efficient, but that the increased capacity would simply be filled with more high-paid workers. The city would have to

I'm not arguing that urban density is less efficient, but that the increased capacity would simply be filled with more high-paid workers. The city would have to throw up a ton of housing projects to have an effect on the median housing costs. IMHO it would be better to spend that money transforming the transportation and public education systems...