They've both implemented opencl. Nvidia has too. The industry could have built on that common language. Instead, it built on cuda, and complains that the other hardware vendors don't have cuda.

I attribute this to opencl being the common subset a bunch of companies could agree could be implemented. I wrote some code that compiles as cuda, opencl, C++ and openmp, and the entire exercise was repeatedly "what, opencl can't do that either? damn it".