Ya but that's my point. Players are people too not just representatives of a region that don't care about income, family etc. When a player is good enough that other regions consider them, that opens up options for them to move and maybe make more than they do at home. Bjergsen would not make what he does on TSM on any EU team, so financially and in terms of long term overview it is a great option for him to move.

Zven and Mithy are amazing players, easily among the best bot lanes in the west. If a team like for instance Team Liquid who has good assets and looking for a bot lane replacement was to offer them a far better deal than their current salary at G2, I would definitely understand them moving, and I don't think it should be regarded negatively because from their personal point-of-view it is the best decision.

The question you should ask when that happens isn't, whether we can tighten the hold of players and FORCE them to stay in their region, but rather what is holding back organizations in for instance EU from obtaining similar funds to sustain their players salaries at a comparable level to the other regions, and then try to find ways either through for instance crowd-funding, Riot support, etc to help prop up that scene and encourage players to stay. I personally hate this system Riot puts in place that artificially restricts the number of imports instead of trying to help regions where the teams are struggling to pay higher player salaries to discourage them from leaving.