It depends on the game; notably, FFXIV does not allow trading most of the drops you get from the boss fights, so anyone that has a rare mount from one of those "earned" them themselves.

Of course, there's also a market for characters - there's bot / player farms of people leveling characters and acquiring these rarities which then get sold to whales. I don't believe it's a particularly big market though.

There is also a market for leveled characters, as people don't want to spend the time to do so themselves, but they (and I'm sure all other MMOs too nowadays) offer a paid for level boost that takes you to the current max level - 10, at a price point that directly competes with bots.

One issue XIV still has is gold farming and selling bots, they don't offer a means to directly buy gold. Closest thing is buying pure white/black dyes for real money, which can be sold in-game. I suspect it's a PR tradeoff, that is, "boo at people just buying gold".

Of course, XIV has a bit of an inflation issue I think, not enough money sinks. They'll add a new mount that costs 7.5 million in an expansion which will remove some money from the economy, but I don't think it's enough.

Poker is also skill based and also gambling. The concept that gaming lootboxes isn’t gambling because there’s some tangential element of skill involvement is just a strange way trying to protect something that is obviously gambling. It’s not complicated. The only complicated element is that these business grew large enough to get lobby orgs influencing politicians before the law got effectively enforced. You won’t ever see a casino with kids running rampant getting away with a shrug and “how are we going to enforce age restrictions” yet gaming companies get away with this all the time.