"So that leaves one large CPU player, Intel, with... who?"
This doesn't really cover the full breadth of Intel's product line - while CPU's make up the majority of their products, before the 10nm debacle they were looking at dominating a significant chunk of the market from flash to CPU's to analogue (4G/5G) to machine learning.
Who wants Intel HD graphics? The vast majority of the market.... Intel's onboard offerings which are now roughly equivalent to mid-range discrete GPUs from 3-4 generations ago and Intel have increased their market share over the last 10 years from ~50% to ~75%. Yes there is a big gap between the top of the range discrete GPUs and Intels offerings but that is a small slice of the overall market and Intel would be competing against console/AMD/nVidia for that.
The reality is that instead of GPU's, Intel has done "enough" and is trying to compete against nVidia in machine learning. While Intel are losing at the moment, they are constrained by their process technology (again) and historical choices where they focussed on CPU's. Both nVidia and Intel have purchased companies to try and address the limitations and I wouldn't count either out of the machine learning race just yet.