Also there needs to be sufficient talent available across all roles needed, to completely move the company to a new location. As opposed to just a lot at the low end of skills. The cost and other downsides of that move would also be immense.
Perhaps one day remote work will be far more common, and I think this would be a good thing, by the way. I also think brain drain is bad overall. Developing countries need those productive residents far more than the west does.