Definitely, the UI to sideloading is a real problem. But Youtube would be unusable for me on Android without NewPipe, it helps so much.
I'm not really arguing that this is a great solution for everyone (or that sideloading should magically mean that Android isn't being noncompetitive), just pointing out that even insufficient solutions can really make a really big difference for some people.
I want the sideloading and updating experience on Android to be better, and there are some very real frustrations that come from that -- including that there are great apps like NewPipe that I can't really recommend to everyone I know because of the complexity of installing them. But in contrast, I don't think I could even use iPhone myself because these apps are so essential to me, so I'm grateful that at least I have a phone where it's possible for me to jump through these hoops.
To your point though and in regards to the person you were replying to, you're right that none of that changes anything about whether Play Store has what is essentially a monopoly over other Android storefronts. I would love to live in a world where I could recommend NewPipe to people without feeling like I also need to borrow their phone and sit down with them and help them install it.
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> For us (well, atleast me), getting an apk from github is not a problem
Pro tip which you might already be aware of, but F-Droid supports custom repositories, and the NewPipe team maintains their own repository that gets immediate updates. Installing NewPipe from F-Droid directly isn't something I would recommend because the app needs to be updated so frequently and F-Droid is slow to pull in those changes. But if you use their custom upstream repo, you can still have F-Droid manage the updates/installation while getting basically direct updates from the Github repo.
This would of course be better if Android allowed the F-Droid store to auto-update apps, but...
I vaguely remember hearing that at some point Android was going to allow this, but then I haven't heard anything since and my version of F-Droid still requires manually clicking an install button, so I'm not sure if Google ever actually followed through.