The main reason most game economies go tits up is almost always unilaterally bots and sybil attack. It is a higher priority to sell the game and turn a profit for the corporation than to ensure the sanctity of the in-game economy. Banned a cheater? Let them pay another $60 for a new copy of the game and they can start cheating all over again. Cheater wins, corporation wins; everybody's happy! Except for the actual players of course.

It's like when a bank gets a fine but the fine is less than the profit extracted.
There is zero incentive for the cheater to stop.

Especially true because cheaters are banned in big batches so they are actually allowed to keep cheating even after they've been caught (they will be banned during the next banning wave). The reason to do this is that if you ban them in real time it's far more likely they'll figure out exactly how they got caught and then tip off all their other cheater friends so that they don't get caught. This is actually a huge business and there are literal gangs of hackers that make money together doing this. Those gangs even have enemy gangs and will rat each other out and make sure the rival gang can't get an "unfair" cheating advantage lol.

The real solution to all of this is for the community to regulate itself. I want to make an invite-only system where the community has to vote to let you in, and someone (or multiple people) have to vouch for you. If you get banned for cheating it looks bad on them as well. The community and players need to be the police of the server and not some centralized company hiring some underpaid game-master who doesn't actually give a shit.