Yes, I accept that they need continuity and so can't have characters leaving Ambridge in droves. However, they live within commuting range of Brum and (at a stretch) London, so they really could have had a wider range of careers. On the odd occasion that somebody has got a job in a city it's always been far too much for them within a matter of weeks. Mark Hebden was a young, healthy man with no children and still found it far too much to drive to Birmingham every day, so left his big law firm and set up his own practice in Felphersham. Brenda had conniptions about working in Leicester. Jill fretted constantly about Elizabeth living in Brum and of course before long she threw in the towel and came back to work for Nigel.
Re suddenly getting married while still quite young - I did that. It isn't always a disaster. I was 21 when I married and my husband was 27. We were both still students. I finished my degree and went on to get a professional qualification. Still married (very happily) now.
I also know a young woman a little over 30 who is doing extremely well in her academic career. She's been with the same chap (a few years older) since she was in the sixth form. She chose her university based on where he was going to be working (the MNers on the HE threads here would have had conniptions about that). It wasn't a top ranked place but by her own account she spent most of her time in sixth form drinking and partying, so a top ranked place was not really an option. At university, though, everything fell into place and she got a First, moved to a much higher rated university to do a Master's, got a Distinction, secured a fully funded Ph.D. position and is now on her second postdoc job (fellowship, extremely prestigious). And all the time she has been going home to this lovely man who does a job not dissimilar to Chris Carter's. They are blissfully happy. Love of cats seems to have a lot do do with it. I would like to think that Alice and Chris can make it work in the same way.