If you're talking about cities like Seattle, the reason that a 30-year-old hairdresser would have a difficult time purchasing a place is because prices have been pushed absurdly high due to two factors:
a) a housing shortage (primarily in the SF Bay Area, but Seattle has similar problems, and the SF housing problems spill over into other nearby cities)
b) speculative purchasing by foreign entities
The second point is less relevant Seattle than it is to nearby Vancouver - and nowhere is it more true than in New York City - but it still has a huge inflationary impact on property values in a way that doesn't benefit any local residents at all (the properties are used as places to park money by people who don't live there, and may never even have visited the US).