Real estate prices are also part of the problem, especially in urban cores... some Seattle and SF rents are just stupid, to say nothing of NYC
If people earn more, they can afford a bigger mortgage, so house prices rise.
I would like to see some stats on that meme.
Anecdotally, what I think happens is that people buying second homes, vacation homes, and more people living one person to a home. People without homes are not clearly advantaged.
I live in Christchurch New Zealand, with a truely massive increase in standalone houses, and significant densification in the city center. However house prices are still booming, and plenty of friends are struggling to find a first home.