I'd love to see this with additional data on property prices vs. mortgage rates, financing vs. purchase rates, volume (residential units sold), CPI inflation rates, and monetary issuance (M2 supply).

I suspect the underlying correlation is primarily due to accumulations of capital by institutions and the ultra-wealthy (mostly through family offices).

High interest rates offer competitive opportunities for those with excess capital and with access to financing collateralized by assets other than the real estate being purchased.

The "costs" shown in this graph are mostly for the riffraff.