Is it that prevalent? Seems like anti cheat works, at least I don't see much of it in the games I play. Are y'all seeing cheaters frequently? What games?
It's to the point now where they are using DMA (direct memory access) cards to read memory directly from the PCI bus and bypass even the most invasive anticheats. Valorant has a ton of DMA cheaters.
For the cheaters? A feeling of superiority. For the people that make those cheats? Money from those losers, apparently enough to be worth the trouble sadly.
CS2 is at least 1 blatant cheater every match that I play (spinbot, anti-aim, walls, aimhack). They react to things they cant see, shoot you through a smoke and a wall with no hesitation and generally dont hide it that well. You can even watch the demo back to see them lock onto someone they havent heard or seen through the wall and follow them perfectly, reacting to what the other player does without seeing or hearing it. Vac has been a joke for years and even now with "Vac 3.0" i havent seen a single person get banned
GTA Online has so many cheaters/hackers/modders that it can be unfun to do anything in it since they are either the type to give away free money or the type to grief you and crash you.
In Oldschool Runescape it's pretty common to see characters that are just blatantly bots. If they had plausible usernames and picked a random appearance it wouldn't even be that obvious, because it's a whole game about repetitive actions, but a lot of them have the default appearance and gibberish names.
Botting is sort of a different problem because it's often related to real-money trading, so there's a more obvious incentive to cheat: running bots generates gold that can be sold for cash.
In addition to that, many people run bots as a sort of side hustle, either to fund their main or just to fund more bots. And I suspect many people use scripts to automate tedious tasks on their main accounts as well, although that would be hard to notice unless you directly interacted with them while they were AFK.