Although I disagree with some of the points (which have been mentioned in other comments), I do wish Steam had less of a monopoly. That's not to say I blame Valve, I just think there is a lack of good competitors and people willing to budge. Epic launcher is just a joke. I only use it for the free games, which is why I assume they are giving away the games for free in the first place. Not enough people use GOG. Thankful to Valve for making proton, Linux gaming would be a lot worse than it is if it weren't for proton. But damn, make a 64 bit client already, I have to use the multilib repo because it is the only 32 bit application on my system XD. EDIT: not to mention the terrible performance on some older systems.
I saw this posted a couple days ago which pretty succinctly summarizes the current state of the market.
That said, worth noting that these launchers and complex storefronts aren't really needed either, which is part of why I don't have an issue with Steam. If you have a good game, you can just sell it on your own website like Minecraft, League of Legends, or Tarkov. Steam's biggest (or at least most universal) utility for developers is just that it provides very cheap, very effective marketing.
Insofar as your point is a call to action for Steam's competitors to do better with their own services, I completely agree with you. Epic & OP are whiny bitches with half-assed output that expect to be taken seriously without putting in the work. 🤌🏽
True, although correct me if I'm wrong, people have issues with the flatpak version? I apologise if I'm talking out my ass, I couldn't tell you what these "problems" are. It may just be a baseless claim. XD
Maybe not. Like every new format, Flatpak probably had some rough edges at first, and a software as complex as Steam must have been a nightmare to convert. It was probably broken at first, but it was probably enough for some to consider it as unredeemable.