Maybe I missed it being discussed here, but without seeing the data, housing costs seem to be a huge factor as well. Even in the 10 or so years I have lived in my area, here I live, the cost of the average home increased from around $150,000 in 2011 to around $390,000 in 2022. Rents are even more out of control, with 1 bedroom units frequently being in the high thousands, low 2s per month.
We are a bit of an outlier because DFW has experienced rapid growth for a while, but costs have risen everywhere. As it pertains to younger people, its a double hit because (a) home ownership has historically been a huge factor in growing wealth and it is increasingly a lot harder to get into and (b) renting, which isn't an investment in anything except a roof for a month, increasingly costs more than a monthly mortgage payment these days.
We were very luck to have been able to buy during the last decade, but know quite a few people who cannot or have gotten into homes at a higher debt/income than we have. That has a massive impact in the long run one would think and is a part of the income insecurity as well that impacts both millennials and Gen-Z, given how home equity provides a number of paths (ie. Home equity loans, HELOCs, etc.) to those who own homes (which generally skews toward older generations) that don't exist for those who don't (skews younger)