> on Android, it's just as customizable as a Linux desktop
I wouldn't say is true. For android launchers to be functionally equivalent to (or as customizable as) linux DEs, they'd have to be able to customize android's nav bar, pull-down menu, settings app, recents menu, and split screen/tiling/windowing. At the moment, these are all handled at the OS level. Not that android's launcher concept isn't cool, but it's definitely not as flexible as DEs.
I agree, the launcher isn't as customizable as a linux desktop. To change the entirety of a linux user interface is much easier on a linux desktop. But nonetheless, Android is still quite customizable, and the other interfaces you mentioned (nav bar, pull down menu, etc) are still customizable if you're able to flash a custom ROM. It's all possible, but desktop Linux is much easier to fiddle around with in that manner.
Nonetheless, I think Android should've been left out of that group in the OP. Not a big deal, but for someone who used to tinker with Android quite a bit, I couldn't resist commenting the point.
> on Android, it's just as customizable as a Linux desktop
I wouldn't say is true. For android launchers to be functionally equivalent to (or as customizable as) linux DEs, they'd have to be able to customize android's nav bar, pull-down menu, settings app, recents menu, and split screen/tiling/windowing. At the moment, these are all handled at the OS level. Not that android's launcher concept isn't cool, but it's definitely not as flexible as DEs.