Do you also believe that moving town/province within the same country should be restricted? All your arguments about brain drain prove too much, what about the brain drain from Small Town, Kentucky to Los Angeles? Either you think that migration from Small Town should also be restricted (monstrous), or there's a reason why moving country is qualitatively different, why country lines are special. Make sure you take into account that country lines are drawn essentially arbitrarily, according to the particularities of history, not any kind of coherent principle.
Well it’s good enough for the CCP…
Seriously though, I am going to give you the benefit of the doubt that you are 13 and don’t really understand what a country/government/nation state does and how they work yet. A “country” has a single tax pool that funds much of the national budget. Obviously every nation handles this a little differently, and situations where governments merge (eg. German reunification) are a little more complicated, and some countries tax their overseas citizens. But overall, if you move from NY to LA, you still pay taxes to the United States federal government, and receive similar benefits from it. If you move from eg Haiti to the United States, you may choose to send money to your family and friends in the old country, but your taxes go to the United States, not Haiti. Now, there are countries that are so short of anything but human capital that most of their GDP is remittances (money sent home by migrant workers), but this is not a great long term base for an economy for multiple reasons.
Country lines are NOT drawn arbitrarily generally speaking. Post colonial state boundaries were often drawn up by colonizers half a world away without much regard to local conditions… which resulted in rather a lot of conflict in post colonial regions as internal and external violence occurred to move national boundaries or people into more stable locations. Country borders are where the corpses of soldiers pile up, attacking or defending; they are boundaries of blood shed and projection of force. They are anything but arbitrary. It’s not a “particularity of history” that the last war left the borders in a particular location. Occasionally borders are adjusted by polite negotiated agreements between nations, but this usually involves extremely small areas and territory swaps or officially renouncing competing territorial claims. Still not arbitrary.
Brain drain is indeed a problem for bumfuck towns from internal migration within the West, however there are reasons for businesses to set up in such places (The American south is a popular region for such ventures due to low cost of living and cheap labor)… and they’re all under the same government. If I start a manufacturing plant in bumfuck West Virginia, my products are manufactured in the United States and are not subject to tariffs or import restrictions, and also don’t have to be shipped internationally (expensive for bulky and heavy items, an issue for perishable goods too).
