So why would you have to move to create a concentration of "human educational capital"?
In person-contact with teachers and classmates, physical access to labs, etc., seems useful enough that most people are still educated at physical institutions. And for obvious reasons it's often easier for them to stay nearby after they graduate. And it's therefore to the advantage of employers to locate nearby.
Similarly it's often more effective for coworkers to work physically together. And if you're a company trying to decide where to locate an office, locating it near potential employees--which probably means locating near lots of other companies in your field--may be attractive.
you don't see all those jobs that were outsourced to India requiring that their workers move to North America or Europe.
But they may be required to relocate to Bangalore, for example.
Personally: starting next month I'm working from home with my nearest coworkers hundreds of miles away. But I also live a few minutes from a significant number of the other main developers in my field, who work (also from home) for other companies.
Locality in the age of the internet may turn out to be more complicated than you'd expect.... Instead of leaving people distributed homogeneously across the globe, it may just enable them to clump together in different ways.