It's not arbitrary, I'm just sampling the most populous because that's typically where the increases have allegedly been the most dramatic. The intention behind choosing only the top 10 is to be as minimally charitable to my own point as possible.

In the top 20 most populous MSAs, only 7 experienced a substantial multiplier increase.

In the top 50, it's even less.

The further down the list you go, the less likely there has been a dramatic increase in home-price-to-income ratio.

There's a whole collection of "Fine, American cities" (https://twitter.com/jmhorp/status/1221828340656431105) where multipliers have either not increased, or decreased.