The question is not AMD's processing power, the question is the tools available for AMD cards, which are scant to say the best.

While AMD doesn't create something like cuDNN to go along with their cards, no real work will start being done in porting most important DL libraries to AMD cards. And even in that case, it will be a lost generation for AMD, only in the 2nd generation where AMD actually offers a real alternative in DL to NVIDIA, you will start to see some real progress being done with it.