> The moral issue is whether it is ok to take skilled people that have been trained using the limited resources of poorer areas of the world without supplying an equally skilled person in return.

The skilled people that have been trained using the limited resources of poorer areas have literally funded those limited resources through their taxes or by directly paying for their education (private schools are a thing everywhere, even in poor countries -- 1st-hand experience here).

Nobody has a moral obligation to stay in their home country when a much better quality of life is achievable elsewhere. The origin nation does not need to be to "satisfied". Humans should be free agents to defend their best interests and seek a better outcome for themselves and their families, wherever that may be (as long as the destination accepts them!).