Yes, I agree that 30% is a lot. But let's look from another perspective: If a developer, for ease of calculation, sells a game for 30$ on Steam, he receives 20$. If he sells it on a competitive platform with 5% cut (that's 6x less than Steam) he gets 27$.
However, Steam is way bigger, and if a developer can sell the same game more times on Steam (33% more times to be exact), he breaks even.
More people to buy = more people to play = bigger player base => more people buy it. It is a poaitive feedback loop.
I am not arguing that 30% is good, all I am saying is I understand that Steam has to take a big cut to pay for the features it provides for "free" alongside the usual game content (cloud saves, community, workshop, utems, etc.).
To sum it up: about the same as any platform where people can interact? What's so FOMO about a game being on sale if it's gonna be on sale next week aswell?
I fail to see how Steam Market is so bad, it is not possible to redeem the cash (unless you do it via black market, which is against the TOS), so all money is still in the system. Yeah, it is being used to do unregulated gambling, but it's a regulatory problem which should be handled by the countries to define what gambling is, and shut these sites down. Why the fuck should Steam care?
NFTs in crypto space are a joke, and everywhere else they are basically in any online software, failing to see the point here.