My uninformed normie view of the ecosystem suggests that it’s the support for almost every particular board, and that’s exactly the issue. For some reason, ARM devices always have some custom OS or Android and can’t run off-the-shelf Linux. Meanwhile you can just buy an x86/amd64 device and assume it will just work. I presume there is some fundamental reason why ARM devices are so bad about this? Like they’re just missing standardization and every device requires some custom firmware to be loaded by the OS that’s inevitably always packaged in a hacky way?
Answer:
Its the kernel drivers, not firmware. There is no bios or acpi, so the kernel itself has to support a specifc board. In practice it means there is a dtb file that configures it and the actual drivers in the kernel.
Manufacturers hack it together, flash to device and publish the sources, but dont bother with upstreaming and move on.
Same story as android devices not having updates two years after release.