Apparently (from another comment on a thread about arm from a few weeks ago) consumer GPU bioses contain some x86 instructions that get run on the CPU, so getting full support for ARM isn’t as simple as swapping the cards over to a new motherboard. There are ways to hack around it (some people got AMD GPUs booting on a raspberry pi 5 using its PCIe lanes with a bunch of adapters) but it is pretty unreliable.
Yeah, there are some software issues that need to be resolved, but the bigger issue AFAIK is having the hardware to handle it. The few ARM devices with a PCIe slot often don’t fully implement the spec, such as power delivery. Because of that, driver work just doesn’t happen, because nobody can realistically use it.
If they provide a proper PCIe slot (8-16 lanes, on-spec power delivery, etc), getting the drivers updated should be relatively easy (months, not years).
