[Nasrudith]

Technically affordability is peripheral to profit margins - although they are very related right now. If they could make more money and get through building tenements they would because that is where the money is and that is what they can get approved.

In order for cheaper housing to win for new construction it requires both acceptance and greater profit margins.

Granted one doesn't need /new/ affordable housing if the new luxury leaves enough vacancies that the older high end becomes the new low end. The persistent historical lack of high density housing does make things worse because of the lack of dense housing to wind up relatively downgraded creates a bottleneck in density growth for affordable housing. If they were building only new luxury high density for 70 years there would be effectively a relative affordable housing from degradation and shifting designs.