NVidia doesn't have just 3 or 4 engineers in these tasks. When you consider that NVidia just took Google's TPU concept, and basically cloned it into their upcoming GPU ("Tensor Cores"), you realize that NVidia is really pouring millions, maybe hundreds-of-millions, of dollars into AI.

AMD has a number of initiatives that haven't panned out as well as NVidia's AI investment. AMD's "HSA" technology is actually quite interesting, although unpopular. AMD's push for HSA has made it faster at Video Rendering tasks (see Blender for instance) and random tasks like GPGPU-accelerated WinRAR decompression or LibreOffice Spreadsheets.

IIRC, AMD Vega beats NVidia Titan XP in Creo and Solidworks benchmarks (CAD programs). So its not like AMD is sleeping on its laurels here, they're just focusing on other, still profitable, corners of the market.

Of course, the current is behind AI, Tensors, and NVidia at the moment. AMD can't afford to fall further behind. The current trend is AI and Machine Learning, and it seems reasonable for AMD to at least get PyTorch running on AMD cards (if not "beating" NVidia, but at least they can play along).