The steam marketplace is an attempt to monetise the user base by creating a bunch of microtransactions and taking a cut for the store. They have created a speculative market, which is essentially gambling, and made it available to minors. This market is designed to exploit people's psychological weaknesses.

Yes, users and devs get a cut too, and that's better than some sites will do to you, but creating a market also has a bunch of externalities - extra problems that are offloaded onto other people and not borne by valve.

So suddenly we've got a bunch of scammers creating accounts to make money, which obviously can scam users, plus it generats spam, and it creates a need for user-hostile security. Now I can't friend my kid's account without spending money on it for instance,

Also there's the item spam. Now when I get a notification I don't know if it's a community forum reply, or just more worthless junk in my inventory. The inventory could have just been a way to store game gifts and other things of actual value, now I never look at it because it's just full of trash.

Some of these are minor inconveniences, but that's how enshittification happens. It's little, creeping annoyances that get worse and worse until it starts to make people look for alternatives.

And like I said, it's not as bad as other places. Steam is still the best distribution platform out there, but it has enshittified a little bit. It has to, because the interests of the owners and the interests of the users are fundamentally at odds - more money spent means more money for the owners.