My point is only that we can see the value capture of the housing shortage by looking at the delta of housing development COGS and housing prices. I generally agree with you that there is plenty of room for profit margin, but when we see housing prices diverging significantly from lowest-cost construction prices, then we can measure our shortage.

My main point is that, because housing takes a very long time to build en masse, you'd want the housing to start being built before people need it.

It's like any other strategic reserve we have. Since demand can spike, and we can rarely see the spikes coming, but we know they will come, just be prepared by subsidizing the development of that thing. We do it for food, oil, weapons, vaccines, you name it. If we know we will need it in the future anyway, and it take a long time to produce, we create strategic reserves. We should do that for housing.