I’m sorry if this sounds like a stupid question but why won’t android just straight up run like Linux distros that almost run on any computer? Why does each model under each manufacturers require separate maintainors seperately? Aren’t they running like almost similar hardware like processors from Qualcomm, mediatek, Exynos, etc? Why hasn’t there been a single android os that is compatible with all the device?
Let’s clarify some terminology.
Android is an operating system, not hardware. Android uses the Linux kernel, but differs greatly from desktop-oriented Linux distributions. Most phones are designed for Android, a bit like most PCs are designed with Windows in mind.
Desktop-oriented Linux distributions have a semi-standardized software stack with Linux, GNU libraries and utilities, a shell, X11 or Wayland, some sort of window manager or desktop environment, etc…
Other comments have explained how the hardware makes it difficult to have generic operating systems that install easily on any phone like we do for PCs, but they do exist. Ubuntu Touch and PostmarketOS are examples of desktop-like Linux distributions for phone hardware. It’s possible to install and use these on certain phones, but there’s usually a feature or two without a working hardware driver. Desktop Linux on laptop computers used to be that way too, but far fewer laptops have missing drivers now than a decade or two ago.
I have PostmarketOS installed on an older phone. I don’t think the user experience is quite ready for most people to use as their primary phone, even for me, and I’ve been running Linux on laptops for most of my adult life.