I agree about emerging adulthood developing because in our society we are doing things out of order. I went to college, then moved out, had kids, got a job by the time I was 22 and now I'm still in school. I believe I skipped the emerging adult stage since I support my self, moved out on my own, and had kids.
The other thing I thought about, like you did too, was that adults are living with their parents longer because of the high prices of rent and houses in the Bay Area. I was thinking that maybe the Bay area has always had high prices compared to the rest of the country. But I think it might be getting worse because everyone wants to live here because it is where the high paying jobs are and the weather is nice.