I think it's very simple.....the best paying jobs are in outfits/countries that the majority of people do not wish to work. In many cases it means flying with people that have low standards which in itself tends to lower your life expectancy.
Above average money is available to those with training/standards qualifications or who have a specialist skill such as setting up an AOC for a startup. This is usually in a s*ithole though.
Average to good money can be attained by joining an established airline and working your way up the seniority list. They tend to be in civilised countries where you are hit for varying levels of taxes.
Poor earnings can be made pretty much anywhere in the world.
There is no golden goose and no easy fast track route available to the big pay checks.