Raven Molloy, Christopher L. Smith, and Abigail Wozniak write,

internal migration within the United States has fallen continuously since the 1980s, reversing the upward trend that occurred earlier in the 20th century.

Pointer from Richard Florida.

The kaleidoscope is not shaking so much, which may impede the formation of new patterns of specialization and trade. What is that? The authors write,

We find a decline in the wage gain associated with changing employers, but no change in the wage gain
associated with staying at the same employer (i.e. the return to firm-specific tenure). We find qualitatively similar results in the Current Population Survey (CPS) and Panel Study of Income Dynamics (PSID). Although our evidence is only descriptive, it suggests that the distribution of the relevant set of outside offers has shifted in a way that makes labor market transitions—and hence geographic transitions—less desirable to workers.

So, maybe some of the wage differentials that used to cause people to migrate within the U.S. have been arbitraged away. But what about the differential between working and not working? Shouldn’t that be enough to motivate people to change locations?

My answer would be that the accumulation of fragmented means-tested programs has produced a high implicit marginal tax rate on people who do not have steady work. This gets back to the idea of consolidating those programs into a single flexible benefit program with a clear, low marginal tax rate.