The “GPU market” is not an ideal market (E.g. with total fungibility of goods, low non-elastic demand, etc) - Intel has most of the share of GPUs sold because it’s impossible for NVIDIA - or anyone else - to compete with Intel in the spaces where Intel supplies without competition: CPU-integrated GPUs.

On a related note: with PCs now definitely heading towards ARM, this is a sensible move by NVIDIA: they could now sell GeForce-integrated ARM chips for future Windows and Linux boxes - and then they would be the ones with the dominant marketshare.