And salaries may drop precipitously if you are in one of the higher paid countries, because you are now competing with people who may be equally as qualified as you but can make WAY less and afford a very comfortable standard of living anywhere in the world.
Even within countries. Why may San Fran salaries when you just found someone in Fargo, SD that can do the same job and would prefer to stay there.
I realize companies are discussing keeping Silicon Valley salaries wherever their employees choose to live, but that can't last. You could pack up and move to another country and live like an absolute king.