Post WW2 for the boomers was loaded with people flooding to all kinds of industrial boom cities.
After that it was hollowing out of the rust belt and moving out of cities to suburbs due to the lead/crime epidemic.
Then rich cities boomed back with millennials in a continuous feedback loop where the successful ones became more desirable as money brought attractions/activities/restaurants, draining the failing ones even more.
Then 2020 was the brief mega disruption where people thought the internet might catch on and they found out the vast majority of white collar jobs can be done from home so the fanned out to all of the nice and cheap suburbs, mountain towns, etc. Now the Internet fad has worn off so that’s reversing a bit.
Moving in the US has been very common until this brief lull where you could change jobs without relocating thanks to remote work.
Unfortunately we’re going backwards so it wouldn’t surprise me if constant relocation resumes.