This isn't GNU/Linux specific either, Android has the same problem. Every OEM wants to be Apple, but doesn't want to do the work of maintaining a full vertical platform.
This incentivizes them to make decisions that are actively user-hostile (such as pushing out updates more slowly because they need to update their custom UI stuff).
We see the same dynamic playing out on the GNU/Linux desktop: Ubuntu, Fedora, Pop OS etc. are pretending to be platforms, but they're not.
This results in a situation where everyone is trying to do campy "value-add" features, and pushing their brand in users' faces. It's why atrocities like the Fedora logo extension, and developer-hostile custom system stylesheets are a thing even though everyone knows these are bad ideas.
Of course it's a little different on Android, because Google has long made Nexus/Pixel devices, which ship a clean version of the platform without OEM "improvements".
But even on the free desktop there are examples of this: elementaryOS is famously vertical by design, Budgie has Solus, and even KDE has Neon. We're the only platform that you *can't* get without going through a distributor.
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