I wonder how meaningful the "remote work" is, considering the legal issues of hiring workers from another country? What if there weren't any? Time zones aren'

I wonder how meaningful the "remote work" is, considering the legal issues of hiring workers from another country? What if there weren't any? Time zones aren't always the problem, high-speed internet is often common, lots of IT jobs are location-agnostic. It could have a serious impact on the job market - what is poor in USA is upper 1% income worldwide, so an ability to get a remote job at USA prices can make local jobs uncompetitive by huge factors. What sort of effects would this have on the world? Or is it meaningless speculation anyway, since the legal restrictions aren't going away in any plausible futures?