Being the most favorable game market does not mean "there is no competition". It's just the competition is doing it wrong so everyone flocks to what they like or have stuck with.
Microsoft and Epic take less because they have less. Both their ecosystems are shit. They are also trying to get into the market, once they own a decent share of it they are hiking that right back up. Gaben is smart leaving it how it always has been, while continuously improving the platform.
People don't like the 30%, but they are still choosing steam because it's the better platform. Epic and co are the ones who make things exclusive and try to corner the market.
The article points to a "similar case with sony", but it's not similar really. Sony has exclusives too.
This entire article is shit and there's no victim here, except Microsoft and Epic maybe. This is a class action lawsuit nobody asked for.