[asveikau]

I think I'm several years out of date on this issue, but years ago one of the problems was that there were not standard hardware interfaces for things a kernel needs like interrupt routing or hardware bus enumeration. The PC for example is a very homogeneous platform. There are also standards like EFI. But the ARM world has been a wild west. Each device needed some kind of hardcoded hardware map.

[wolrah]

That explains why ARM mainline Linux is more of a mess than other platforms, but it doesn't explain why ARM SoC vendors are seemingly entirely uninterested in doing things the right way. They could develop in a mainline-compatible way and work to upstream their changes so their platforms could be supported properly ~forever but they instead seem to go out of their way to do the opposite despite constant pressure to fix their garbage.