I really think Valve have become the de-facto owners of the “don’t be evil” motto nowadays, even if they don’t advertise themselves as such.
They got and have maintained that monopoly (I'll let others debate the merits of that wording) by being very very good to their users, which doesn't make the existence of the monopoly evidence that they aren't saints. If they were maintaining it through anticompetitive means, sure, but I've never seen anyone claim that they are, even Epic (who would definitely be making noise if they thought they could get anyone to listen).
The desktop video gaming ecosystem is in perhaps the best shape possible: there's one clear winner at the moment who makes all customers very happy, with a few runners up hedging against that winner becoming abusive after all. If Steam became worse than Epic it wouldn't take long for Epic to overtake them, but as long as it's not worse it's nice that everyone has agreed on a standard platform.
Helps that they don't have to be very very good to shareholders that don't give a fuck about games and just want money. I'm not really looking forward to find out what happens once Gabe passes on control of the company.