As long time cheater on GTA V (not that stupid annoying kind that wreaks havoc on the server) the game becomes boring after time and you have to figure a way out what else to do. In GTA it's random fun with spawning cars, money etc. in competitive games it's probably to have some feeling that you are better than everyone else (even if it's not true at all). Probably most of the cases are just noobs that needs to boost to higher ranks to be "better" or so they can sell the account fast.