Less and less of AOSP is being updated also, as Google rolls most of its new features and updates behind the Play Services system. Install Graphene and you will see what I am talking about - the SMS app for example hasn't been updated in probably a decade and looks and functions like it did back in Android 4 (KitKat). Same with the other built-in apps. While I used Graphene myself for a solid 6 months, the features you have to give up on using or find some obtuse workaround for aren't appealing to the "normies" who just want their phone to do what they want, no matter the unseen ethical cost (in this case, sacrificing the ability to freely install 3rd party apps).
Someone on another forum said it very well - people like "us" were Google's foot in the door, now along with Apple they have such a stranglehold on the mobile OS space that a 3rd viable and comparable contestant becomes less and less likely by the day.
Throw in how Google starting with Android 16 is not releasing updated drivers with AOSP and Graphene probably doesn't have much life left in it, either.
Regarding 3. Battery life - I’ve had a ThinkPad Nano for several years that, on Windows 11 would get roughly 4-6 hours battery, and this was optimized (very few running apps, no junk on startup, power saving settings on, etc). I switched it to Ubuntu (I was surprised that everything worked out of the box too, all of the hot keys and everything), and it will get about 8-10 hours doing the same tasks (primarily Chrome). So there is something to be said about Linux in general just being so much more “light weight” so to speak vs windows, which has become such a bloated mess.
But the main issue I had was your point 4, since the thinkpads screen is 2K, everything was either too small (with no scaling) or too big (with scaling on).