thanks! yeah, rereading it is a bit of a tautology, and approximately fixed number of units is the basic point. the reason for emphasizing it a bit is just to make clear that demand is diverted, for a given aggregate housing budget, sudden interest in some units doesn’t change the average cost. 1/

so it’s invisible to price level measures. that’s also a tautology, basically the definition of average. but i think people’s intuition is that price spirals in high-demand automatically lead to aggregate inflation. 2/

in practice they might, probably do! but only via the channel of sucking in new purchasing power. you can decompose an an inequality of quality, redirection of demand effect from aggregate purchasing power changes, and the former have welfare effects invisible to price level measures. 3/

(this all should have been stated more clearly.) /fin