I don’t really see this; All of the currently popular machine learning frameworks either support GPU or are oriented around GPU based execution. For most developers working on AI it is still the defacto standard.
GPU's are the engines that made CNN's (in particular) tractable, and opened up a bunch of applications for many companies, and opened up a reasonable route to results for a generation of researchers.
This isn’t to say that GPUs aren’t nice. They do save time or for the same amount of time let you produce more polished results, which means in a competitive environment everyone would use them.