Why would they pay? It's a 10-year-old game that's the second best selling game of all time. Rockstar made their money, and there isn't anything a competitor could use to gain an advantage. It's almost good because it's free press for GTA VI.
2. GTA online brings at least half a billion a year in microtransactions.
[0]: https://fivem.net/
this will just serve as yet another feather in the cap for the exploit/hacking/modding community; and a lot of THOSE people make cash by selling exploits.
If rockstar cared about cheating ( they don't ) this would throw a big monkey wrench into that effort, obfuscation is half the battle in a game where book-keeping like an MMO would be performance prohibitive.