By the way, if match-fixing is well organized, it is very difficult to detect. Of course, it is more common in the lower leagues, but on the other hand, maybe it is simply more often detected in the lower leagues and poor countries? Sometimes it is so poorly hidden that it becomes noticeable almost immediately. And we only know about match-fixing from those cases that were easily detected. And those fixed matches that remained undetected contributed to the funding of the criminal industry. Do we have the tools to detect well-organized match-fixing? I doubt it.
Not only that, the sport leagues themselves do not want for that information to become public, so even if they knew there was some match fixing going on, it is likely they will choose to hide it instead of actually investigating what is happening, because if they did so and they found out most teams and players were engaging on it, then they will lose the confidence of the fans and their support, bringing massive losses and it could be a blow from which they may not recover.