The house you’re in just keeps getting more valuable as supply remains tight and rates tick up from where they’ve been. So nobody’s putting their house on the market, which then compounds the supply problem.

Nobody wants to sell their house because (a) they’ll have to jump out of a sub-3% mortgage (if they’ve refi’d over the past couple years) into something higher, and b) they’ll just have to buy another one, and with how prices have skyrocketed, they won’t be able to get as much house as they already have, again, compounded by an uptick in rates relative to what they were.

Seems like a consequence of having dropped rates to absolute rock bottom while there was simultaneously constant, heavy demand for housing.