Well, the problem is that Intel started with something way worse than OpenCL when they brought their first Phi to market: OpenMP. The claim was to just wrap your loops in OpenMP directives and everything will be fine. Yea well...
If they had went full on OpenCL, including a unified programming for vector and multicore parallelism (the way CUDA works), I think Phi might have taken off much more already.
If they had went full on OpenCL, including a unified programming for vector and multicore parallelism (the way CUDA works), I think Phi might have taken off much more already.