I don't think this is simple econ 101. Yes with more houses we should expect lower prices, but also with high prices we should expect more houses produced. All that is econ 101, but that second econ 101 prediction isn't happening. I would guess that some will chalk it up to vaguely (though not necessarily wrong) jerks/idiots blocking it. Whether it's because nimbyers want to keep their home values (what we should expect from econ) or it's broken city politics, there are lots of things going on here. It's more complicated.