Same as this is the gambling, more key players are involved with match fixing even after getting huge sum of money after every match winning/losing. Why certain sportsmen have such greed towards money when people are starving to have a single meal on a day.
Game fixing can only exist if the regulators and the governing body failed to monitor, catch and prosecute those who are involved in game-fixing,
those who are involved in game-fixing mostly are not superstars in the league, these fixers can make huge money in a few games more than they can in a year of playing.
There should be no game fixing and all governing bodies must ensure that none can exist, that is why they impose very stiff penalties like banning those involved for life and their license revoked.