> It has to play out long enough for the market to indicate a preference
By what measures hasn't that happened already? CUDA been around and constantly improving for more than 15 years, and there is no competitors in sight so far. It's basically the de facto standard in many ecosystems.
SYCL is the quasi-successor to OpenCL, built on the same flavor of SPIR-V. Various efforts are trying to run it on top of Vulkan Compute (which tends to be broadly support by modern GPU's) but it's non-trivial because the technologies are independently developed and there are some incompatibilities.
By what measures hasn't that happened already? CUDA been around and constantly improving for more than 15 years, and there is no competitors in sight so far. It's basically the de facto standard in many ecosystems.