That's true of a lot of large cities in that age group - as you start families, you tend to start to value cheap housing (for more space) and good schools more

That's true of a lot of large cities in that age group - as you start families, you tend to start to value cheap housing (for more space) and good schools more than you do when you're single. I remember a stat that said if you move to a city after you're 30, you have a >50% chance of staying there long term, and that's why cities will target that age group when trying to get people to move. I'm guessing that means for people 20-30 the % that stay in a city is less than that, so it would be normal to see most folks you know eventually move out of town in that age bracket in a major city. SF has a lot of turnover, but the few studies I've seen say it's not particularly high by US standards. Nashville, for one, is higher. (Notably this study is by MSA so it wouldn't consider someone moving from SF to say, Burlingame a departure.) https://www.abodo.com/blog/so-long-to-the-city/ https://www.abodo.com/blog/so-long-to-the-city/