Sure, many games are tied to various Steam services, but that's by the choice of the games developer. Steam offers various built in services that game devs can choose to use if they want. It's not like it's some kind of requirement.

You might as well complain that game devs use Windows binaries, locking their games to only run on Windows. Sure, I prefer it when they target other platforms, but that's 1000% not Microsoft's fault that the dev chose to dev for their platform. I'm not mad at Microsoft for so many games being Windows only. I'm mad at the devs.

And games that build themselves around Steam services are of course going to be tied to Steam. That's a choice the devs made. If they wanted their game to run without needing the Steam client, they trivially could have built it that way. They just would have had to either reimplement all those Steam features themselves, or done without.

And if people want those Steam features, every store client who wants to run those games would have to implement those features in an interoperable way. It's easy to say "have interoperability between clients," but that's glossing over the potentially thousands of dev hours required to implement all of the features needed. And that's assuming they could all agree on a spec.

And to your final point about being open source. First, it gives very "any musician who gets paid is a sellout" energy. But more than that, it doesn't actually solve the problem you have. Even if Steam open sourced their tooling, that doesn't mean other players in the space could integrate it. Steam has grown organically for the past 30yrs, and trying to extricate the deep inner bits and then graft them on to your own solution isn't as easy as it sounds.

Exceptions mean there's no rule, yeah?

1. when you're arguing that it's impossible for a game to make a profit without Steam, yes

2. my post was in reply to you listing a single game that wasn't profitable for a year and blaming that on it not being on Steam. If my example is not a valid argument then you shouldn't have argued that way in the first place.

https://www.ftc.gov/advice-guidance/competition-guidance/guide-antitrust-laws/single-firm-conduct/monopolization-defined

Courts do not require a literal monopoly before applying rules for single firm conduct; that term is used as shorthand for a firm with significant and durable market power — that is, the long term ability to raise price or exclude competitors. That is how that term is used here: a "monopolist" is a firm with significant and durable market power.

Absolute monopolies do not exist. If there's one asshole selling PC games out of a car boot, Steam does not have a literal absolute monopoly. And yet: not even Epic Games, a bajillion dollar company, has any meaningful impact on Steam's superdupermajority control of the PC gaming market. Steam competitors existing does not mean they matter.