Well, as others have mentioned, jobs are risky. You can lose them for any reason at any time, and leaving your support network is a bad idea in that case. This has always been true. It wouldn't account for why people are now less likely to wish to move, but I think housing prices do.
Right now, a person may have an affordable mortgage at a very low fixed interest rate. Yes, he/she may have more than $150k in equity due to the insanity of the housing market, but that likewise means that all of the other houses have gone up by as much if not more in price. This makes moving very unappealing, and more so if the place to which one is being asked to move is San Francisco, New York City, or some other likewise expensive location.
Right now, a person may have an affordable mortgage at a very low fixed interest rate. Yes, he/she may have more than $150k in equity due to the insanity of the housing market, but that likewise means that all of the other houses have gone up by as much if not more in price. This makes moving very unappealing, and more so if the place to which one is being asked to move is San Francisco, New York City, or some other likewise expensive location.