You'd need to either have drivers in the kernel for everything, with no common fallback ("the ARM approach"), or have standards at the hardware/HW firmware leve

You'd need to either have drivers in the kernel for everything, with no common fallback ("the ARM approach"), or have standards at the hardware/HW firmware level. Having a firmware-level abstraction layer that papers over this for fallback may not be the best idea, but it works without too much politicking.