Availability is one thing, driver support is another
The choices at the moment are :
Nvidia - fast, expensive, decent closed source driver support. Terrible open source driver support. Works well with PCI-e passthrough.
AMD - marginally cheaper, less functional, faster in some areas/slower in others. Consistently lacklustre closed source driver support. Open source driver support that improves over time. All but one specific enterprise card react badly to PCI-e passthrough last time I looked.
There is room for a card that's fast enough, stable, with great closed and open source drivers. Hopefully Arc can be that, and support PCI-e passthrough too.
Now, if you'll excuse me, I need to try and get FreeBSD working with my AMD Vega 56. The card that finally gained stable Windows drivers 6-12 months after its successor was released, and where amdgpu under FreeBSD now has better Displayport MST support than the Windows drivers which produce corrupt images, blue screens, or no image in various topologies. The same topologies work fine under amdgpu as mentioned, or under Windows with the Vega chipset built into a Surface 4 (go figure!). Maybe AMD will fix this soon, but it's been a whole theme of things that work well under Nvidia or are fixed in a timely manner, as opposed to pain and a lot of waiting for AMD.