> Not in sf or nyc.
It's still trivially true that most people in SF and NYC, including married adults with families, get by on way less than $150k. Even Upper-East-Side Manhattan, one of the wealthiest zip codes in the U.S., has average incomes "only" in the high 5 figures. Maybe there is a small section of Nob Hill where $150k incomes are normal, but even in most nice parts of SF that's not a typical family's income.
Part of the reason is that in areas where housing is the major cost, the 40x-your-housing-cost rule of thumb is too conservative, and would lead to a conclusion that almost nobody can actually live in the city, whereas clearly many people do. And anyway I believe the usual mortgage-company rules of thumb are 30% of your gross income on the mortgage payment itself, but up to 40% on mortgage+insurance+etc. So that'd lead to $120k in your hypothetical.