[ghaff]

I don't see there being a particular expectation that you'll move to the suburbs (within the rather large confines of that term), although it's quite common for families with children to want more space and better public school systems. However, yes, I do think there's an expectation that people above a certain income level will eventually want to buy some sort of place for reasons of financial diversification and, as you say, stability. There comes a point in most people's lives where the ability to easily pull up roots and move on short notice isn't a particular win but knowing that you can't be forced out on relatively short notice--or face significantly rising rents--is.