That's called real life and using bitcoin as a currency.

it's not just the in-game currency. In an MMO a lot of the abuse comes from duping resources or items. If the in-game economy is secured by it's own ledger then duping resources to dump the market all of a sudden doesn't work cause the internal blockchain would reject any injected resources as they haven't been created in a mining process. 1 sat is just 1 sat so the currency is solid by design. It's everything else that gets exploited in game engines eventually resulting in a crashing eco-system. To go back to CSC MMO, the game had it's own scarcity engine which would ensure that ore, ships, module etc etc were actually created or mined in-game before ever making it to the market.

lol I’ve also spent many hours thinking about this. I just want to play UO and earn sats.

I think a real thing that's not being considered is that real life economies include efforts/capital towards innovation. With mmo economies, the only grind is for existing goods because there's no ability to "invent" items. Thus, all inflation and all grind goes solely towards the purchase of the highest level items, which either have to generated at a rate matching demand, or inflate to infinity because their scarce. Sounds weird, but in game economy would have to introduce "invention" as a natural sink for capital to combat inflation whether it be from in game grinding or external pay-to-win players