I'm not so sure about that second point; I don't see why an independent ARM couldn't provide an effective competition? Server ARMs have been a thing for a while, and Apple has been working on ARM macbooks for a while. I believe the goal is even to completely displace Intel macBooks in favour of the ARM ones eventually.
The big practical issue is probably software compatibility and the like, and it seems to me that the Apple/macOS adoption will do more for that than nVidia ownership.