It's actually not available to most people that live in any third world country, otherwise migration would be significantly higher than it already is.

Regardless, "voting with your feet" is an individual action. Voting at home is a collective one, representing the will of not just you but the people from the place that you come from and were born into. Only one of those reflects the ideals of democracy, if that's really the ideal being strived for

> It's actually not available to most people that live in any third world country

Well sure it is. It isn't easy. There's a difference between available and easy.