Imagine the spouse gets a new job or gets transferred to another city and he moves there to support the spouse. Lets say its a tech company and its the SF Bay Area. He can stay on the 737 in SFO or go fly WB now. Or he gets a divorce and his spouse remarries and moves to the Washington DC area so he moves there as well because of his kids. I know a ton of divorced pilots that moved because the spouse moved. Or they move somewhere that requires a commute no matter what airline you fly for. At least you have more choices with United.

Just pointing out that when you pick an airline that's a mostly final decision, but if you're 35 you still have 30 years of live and anything can happen.

I'm not sure that wrapping my whole career and life around one city is something I'd give much weight to in my decision making.