This has anecdotally been true since forever. Back in the day, OpenCL implementations were passing conformance test but performance was poor. They could not turn hardware capabilities into performance for compute users. Drivers were buggy. Documentation was poor compared to NVidia's docs and forum. Offerings were inconsistent (look up Sycl from Codeplay) and ownership of what it is like to develop for AMD was unclear. The notion that it might not have improved or is only now improving is puzzling. It can't be for the lack of recognizing the problem. Intuitively it does not seem so difficult. I'm curious what the reasons are.
I remember when it came out a little over a year ago, and its just as wrong as it is today as it was then.
After all, if the Software does not work, its just a Paperweight