Intel was never famous for good GPUs, and they are basically the only ones still trying to make something out of OpenCL, with most of the tooling going beyond what Khronos offers.

one API is much more than a plain old SYCL distribution, and still.

I'd argue Intel fell is large part because of Intel's own complacency and incompetence. If Intel had taken AMD seriously, they'd probably still be a serious competitor today.