I wouldn't be surprised in the slightest if they are included in the list. I dunno, I'm not the statistician who crunched the numbers here. I didn't collect the data, and that source material is not available for me to examine.
What I can say is that the article defines "discrete" GPUs instead of just "GPUs" to eliminate all the iGPUs. Because Intel dominates that space with AMD, but it's hard to make an iGPU when you don't make CPUs, and the two largest CPU manufacturers make their own iGPUs.
The overall landscape of the GPU market is very different than what this data implies.