I wonder how much of this is due to supply/demand and the simple fact that more people want to live in about the same number of dwellings. Even if population growth doesn't explain it, urban population growth might. e.g. San Francisco has seen huge growth but constructed basically no new units. So it's not exactly surprising the prices go up.

The funny thing is, all the rich people living in these cities would never be able to survive without all the poor people commuting into the city to support them. The more expensive the city gets, the longer those commutes get. It's a horribly regressive system because now the poor people are spending multiple hours a day commuting, which is a huge opportunity cost of time that they could have spent advancing their social mobility.

At some point something has to give. You can't just keep filling cities with rich people if nobody is there to keep them running.