I don't really get this. Linux and Windows have been bypassing the BIOS ever since 32-bit kernels appeared, yet the same kernel appears to work on every piece of hardware.

Are you implying that x86 hardware vendors are heading towards the same segmentation as in the ARM world, using EFI as a "we're still compatible" excuse? Sadly, it wouldn't even surprise me. But it would motivate me to invest heavily in companies supporting coreboot, such as AMD.