It is well known that there was a brief moment in time when people were abandoning San Francisco and “moving to Texas” (mostly Austin) that coincides when the rents peaked in Austin. I’d be not surprised if that was also the time when San Francisco rents were down.

We’re seeing a reversal in trend when SF is hot again and Austin is not. So not exactly a straightforward comparison. It could explain the SF-> Austin and back trend.

So we've got point in time comparisons between Austin and itself; the change in delta between Austin and a particular city known for restricting housing; and the change in delta between Austin and national median rents. They all support the idea that increasing supply tends to decrease costs, which by a massive coincidence is what basic economic theory suggests.

Of course, people can come up with an ad hoc explanation for why Austin's prices happened to decrease against each of those data points. But is there a single principled way to present the data that suggests increasing supply in Austin did not decrease costs?

Yeah this would be the interesting thing to try to normalize the data against somehow.