Don’t get me wrong – I’m not claiming migration is the only thing that can make governments improve. In case of China there were certainly other reasons (though the successful examples of emigrant Chinese in Taiwan, Hong Kong and Singapore may have played an important part).
couldn't we say the same thing about voting?
There are several important differences.
1) When you choose to emigrate (or switch to Netflix) you make a personal choice and do not force other people to follow. 2) Emigrating would directly affect your life, so you are likely to consider it seriously. Voting does not (one vote never decided a major election), so you are free to make a purely emotional choice.
When I left cable for Netflix... I left one bundle of content for another bundle of content.
Imagine what would happen if only one cable company was allowed to operate in each country (just like the government). Regardless of how accurate is their information regarding your preferences, it is virtually certain that their services would deteriorate. This is an inevitable consequence of a monopoly system.
In several ways you're really preaching to the choir. You might be interested in my recent post here... Is Pragmatarianism (Tax Choice) Less Wrong
Historically, the evolution of government systems was mainly driven by violence, with invasions and revolutions being the principal agents of selection process. The rules of the game were predetermined by our environment - land was a limited resource, for which our ancestors had to compete, if only to ensure the survival of their descendants.
The 20th century introduced a game changer. As agricultural productivity in developed countries rose by orders of magnitude and natural population growth practically came to a halt, possessing a large territory stopped being a necessity. Countries with little arable land, ultra-high population density and no natural resources can now not only feed their population, but also achieve top living standards. These changes may open a fundamentally different route for societal evolution – one that would not be based on violence or compulsion.
A small thought experiment - imagine what would happen if central governments cede most powers to smaller territorial units:
Unfortunately, there are serious obstacles to the successful implementation of this idea:
Do you think these problems are solvable?