> What they fail to miss is that for every luxury unit that's built and is occupied, some well-off person moved into it... And out of a shitty, cheap unit that's now on the market.

Ah yes, good old trickle down economics, applied to housing. It's obviously always true that the people moving into a new luxury home are coming from existing lower-luxury homes in the same part of the same city, and will immediately sell or rent those homes off at prices no larger than what they themselves had paid for them and no more.

And we're basing all of this on a tiny decrease in the prices of new rent offers in one of the most expensive in the USA, which built a tiny amount of extra homes recently, not even clear of what type. Clear causation well established.