I think there are actually two issues here: where should companies hire, and what should they pay those they do hire. The answer to the first question is unequivocally "somewhere cheaper" even though the cost in terms of cultural change and coordination cost can be non-zero. I think it's valid to pay differently in different markets. If an increment in salary has negligible effect on recruitment or retention in that market, it's wasted money. I don't even believe in "shareholder returns uber alles" but I'd rather see that money spent on hiring more people rather than the same number at higher salary.

In my case my employer couldn't have gotten me for too much less, because I did make clear that being an only remote with frequent travel was a negative. That concern doesn't apply equally to everyone, though, and tends to decrease for all as companies adjust to having remotes on every team.