True, I would love for some alternatives such as plaidml. However, I can't seem to fathom that Plaidml will be a worthy alternative to lets say Tensorflow or Pytorch or Caffe. I hope I am proven wrong.
I think support for OpenCI will eventually come to other frameworks. But the main problem is the fact that AMD is still far from the NVidia in terms of performance. Vega couldn't reach the performance of 1080Ti, and with Volta next year, the gap is gonna drastically increase. If only AMD can fill the gap, the support, i'm sure, will soon come after that.