It is costly to move, and those costs vary by culture and economic circumstances. International migration is of course hampered by immigrations laws and cultural barriers. But in most countries, internal migration is free and only restrained by costs and some degree of local attachment. In this respect, Americans are considered to be the most mobile, as they are very willing to drop everything to pursue better opportunities while the housing market is, usually, very fluid. In fact, the perception is that this mobility has even increased in the US and that it has been hampered only in the last few years, due to the current difficulties in selling homes.
Raven Molloy, Christopher Smith and Abigail Wozniak take a close look at the data and dispel some of those perceptions as myths. In fact, US internal migration has been in a steady decline for thirty years, a decline that in apparent whichever way you look at the data: by socioeconomic household characteristics and distance moved. And this has change little with the current crisis, probably because the additional incentive to move (as there is substantial evidence that some structural mismatch, including a geographic mismatch, has increased the unemployment rate recently) has been roughly compensated by the poor saleability of homes. Still, internal migration rates are still higher than almost everywhere else.