Nvidia and AMD (previously ATI) have had a similar relationship for a long time, before ML was a use case. Nvidia has always been the more expensive option afaik. Kinda like Intel vs AMD.
It wasn't in the 2000's back when ATI and NVIDIA cards had comparable prices. Sometimes ATI cost a little more because they were better, but they were never crazy different from NVIDIA.
And there were never supply problems.