I'm guessing it's because many cities still strangle development. "Overbuilt" could be concluded from a lack of feasible projects within a city. There's also

I'm guessing it's because many cities still strangle development. "Overbuilt" could be concluded from a lack of feasible projects within a city. There's also the nebulous problem of investors buying units in new luxury buildings but not occupying or renting them. This could preserve high rent prices as new units are not being faithfully put into the housing pool. Stories about that pop up often but don't seem quantified as an issue.