That's a misguided assumption that doesn’t hold up in practice because it assumes H-1B workers were "brought over" based on employer need for a domestic worker. The need isn't for a domestic worker, its for a skilled worker and the skilled workers want to work in the US because it yields higher compensation and opportunity.

Many H-1B workers request sponsorship from employers despite having the ability to work from local offices because they have in-demand skills that give the leverage to ask for it knowing that it will result in better opportunities.