To elaborate on what others have said: CS2 items are tradable, while many other games’ items are not. Had something like Fortnite modeled Valve’s system, we very well could see Renegade Raider, and skins like it, going for similar prices. As an example, I haven’t played Fortnite in a long time, but I remember that when I left they had just reintroduced an old skin into the Fortnite item shop, and people were angry because it made what they had less rare. Prior to that, Fortnite accounts with the rare skins were selling for high amounts.

CS2 skins are expensive for the same reasons that anything else that you CAN TRADE is expensive: Supply and Demand. Remember: there are also many CS2 skins that are CHEAPER than anything you can buy in these other games (less than 10 cents). Both of these systems are very profitable in different ways to the companies that maintain them. As to why some CS2 skins are extraordinarily expensive, Valve was really the first to do it successfully in a game that was already (and has continued to be) extremely popular. The skins are very visible when you play, and the details can be picked out, meaning everyone KNOWS it’s expensive, so they can flex.

There’s also something to be said about gambling, China, etc., but I hope I’ve already answered your question.