For young people, this is probably the case. I remember being offered an internship out quite far out of town on a couple of occasions, and it was really hard to imagine taking the job. I had no car, and buses out in the boonies are few and far between.
My 22 year old self needed something resembling a large city, and naturally you have the pull of London when you're in the UK. There's the fact that you want to meet people and go out drinking, and you also don't want to cook every night. Professionally, you also need to consider that your first job might not be what you thought, and so having options nearby is essential.
For someone older, maybe with kids, it could work. Anywhere that's large enough to provide a sensible daily routine would work, though you'd need to consider how the spouse will find a job.
It's the kind of consideration that seems to cause London to get bigger and bigger.