Black Crow
Western Airlines accept pilots who have the right to work in their respective countries. However the difference is that these foreign nationals who wish to work in the west have to gain citizenship or become a resident which you have clearly stated. However it is different in Asia, Westerners can come and work without having to gain citizenship or become a resident, so that makes it easier for westerners to come over to work in Asia.
A disadvantage for Asians i believe