Comment by Earw0rm

That's true, but people will willingly sacrifice time for a rather small career step up; moving house is hard once you have a family in schools and so on; so in a conurbation you end up with 1hr+ commutes anyway.

I don't think most are math-minded enough to factor commute time and cost into any salary calculation, if there's a 10% pay bump they'll take it even if all the gains get eaten up travel.