Steam’s de-facto monopoly is so strong, Epic can’t break it. Epic made four billion dollars per year on one game. Epic licenses the engine for like half of all noteworthy games. Epic has the only platform not seizing one-third of all revenue from developers, and that platform throws free shit at customers in constant desperation. And they still can’t move the needle.
Monopoly doesn’t mean there’s zero competition. It means the competition does not matter.
PC gamers have alternatives to Steam the way that Android users have alternatives to Google Play. Yes, there are dozens. And that’s how many users each one has.