How can it be so bad?

Billy gonna learn he ain't ever to old for a whoopin'.

Market dominance ≠ monopoly

I say this because I assume you're talking about Steam, and as a service comparible to the Epic Store, users have A TON MORE options, choices, even more autonomy on Steam than on the Epic Store. Reviews, reselling of keys, reselling of cards, infrastructure to host communities, support systems, bug ticket systems, the competitive sales events, etc.

Not saying Valve or Gabe Newell are perfect, not at all - they are profit driven - and Steam as a store and launcher does have it's own issues.

But as far as I'm concerned the fact that Valve wants to bring commercial videogames to libre open source platforms, something Epic Games is against, is the deciding factor of why I continue to support this behemoth.

With the modern stack and infrastructure of today there is literally no reason not to port games to Linux, unless you want to rely on pervasive, kernel-level DRMs, which are inherently unethical because they take away control from the user and puts it in the hands of a company.

But that's my reason. People have tons of reasons to use Steam, whereas Epic Store is just an exclusivity portal. Also, it's launcher so soooo bad. Not just undernourished, but the UX design patterns make no sense - and when you do that job worse than Valve? Oh boy...

And again, technically speaking:

Market dominance ≠ monopoly

Epic Games, Microsoft, Sony and Nintendo keeping certain fan favourite intellectual property on their store front exclusively? Monopoly. Technically.