I wonder if this is still true once population growth reaches zero or negative. It seems like the baked in assumption of housing is that someone else is going to need it more tomorrow than you do today. I think this is an experiment the U.S. will begin running in earnest in the near future.
That if won't happen anytime soon neither for the Earth in general nor USA in particular. Media often loves to move goals from population growth to agin g population to fertility rate, etc. All those while connected do not negate the fact that population is growing, and growing fast. That 'once population growth reaches zero or negative' is very theoretical and UN is constantly underestimating population growth. So no, we will not see that in our lifetimes.
I think you are missing 'in our lifetime', even though you are quoting 'will double in ~150 years'. Also 'declining every year' doesn't mean it won't start growing again.
Most developed countries will probably run the experiment before us, as long as we can keep the country appealing enough to keep attracting immigrants.
Buy housing in hyper desirable areas that rarely become more dense. Everyone always loves the beach, whether there are 1% fewer humans next year or not.