It sounds a little bit like you're arguing that we should get rid of DRM. The interesting thing is that all of those app stores allow you to import other games. You can already manage your entire computer's gaming library on Steam -- or you could, if the games weren't tied by DRM to a specific client. DRM is literally the entire reason why Epic and Origin have a download client in the first place. If it didn't exist, you could use one client to manage your games today.
I don't see people complaining about GoG or Itch.io on this point, because you can download your games for those systems using a web browser and import them into any game manager you want.
It also sounds a bit like you're arguing for federated standards, which is also a thing that we could do. Nobody complains about there being too many repository remotes in Linux, because you wire them up to whatever package manager you're using and that's it. Your setup doesn't become more complicated just because you're using extra software sources. It's still the same commands to search for software and update your system.
This is already how F-Droid works, and it's great. Anyone can set up an alternative repository to F-Droid and I can use them as a software source within F-Droid. It's also the way that your podcast app works. Nobody complains that there are too many platforms for hosting and distributing podcasts, because as long as you avoid bad actors like Stitcher, you just install one app and manage them in one place from every source.
You're looking at games on the desktop through the lens of the model that Valve popularized by being a dominant player that refused to play nicely with anyone else. There are plenty of ways to design an ecosystem for managing stores without turning your computer into a cesspool of DRM. And Apple could do that, it could build a framework that required 3rd-party stores to work like software repositories.
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Look at all of the fragmented broken systems you're complaining about -- the vast majority of them from video, to music streaming, to game purchases, are fragmented because they are deliberately designed to not work well with each other because the companies want consumer lock-in and DRM. But that's also exactly what is Apple is doing, they're just in a position of power so they're the only people doing it.
People didn't notice that Steam's way of managing games was fundamentally broken until other people copied Steam's strategy and made the downsides obvious. You're noticing the same thing with Apple's app store. You're noticing what goes wrong when app stores are designed using Apple's template -- when they're designed to restrict consumer rights, lock them into platforms, and force competitors out of the market, rather than when they're designed to be standardized clients that serve the user.
> And each App Store also has their own chat system along with the others like discord.
Why does a games distribution platform have a chat system in the first place? Aren't all of those chat systems basically inferior to Discord in almost every way? The Unix way of handling this is that whatever chat system you're using should be able to talk to Steam and get events from that client -- it shouldn't be bundled into Steam itself.