I can't speak to why AMD is so massively incompetent or why they weren't a factor in driving a competitor.
A factor that might not be obvious is that in 2012 CUDA was mostly a commercial failure. Aside from some penetration into oil and gas HPC and things like physics acceleration in games, there wasn't much traction.
Beg your pardon? what does this mean?
https://developer.nvidia.com/gpugems/gpugems3/part-vi-gpu-co...