Maybe 25 years ago. 10 years ago they were commonplace. Intel shipped integrated 3d graphics by no later than 1999:

https://en.wikipedia.org/wiki/Intel_810

Lol I don't know who bought that. Anyone who wanted 3D was buying Voodoo, RIVA TNT or ATI RAGE. Everyone else was happily 2D and running Word 95.

But, to clarify, I was speaking of consumer/mobile. The original iPhone was quite revolutionary for having a decent PowerVR graphics chip. High end symbian phones just had a CPU. See for example https://en.wikipedia.org/wiki/Nokia_6110_Navigator or https://en.wikipedia.org/wiki/Motorola_Razr2

Even though GPGPU was already big in 2008, people still thought of it as a difficult to use coprocessor for big compute jobs. Much as people consider FPGAs now.

I didn't highlight it as a desirable 3d processor, I pointed it out because 3d was essentially becoming default at that point.

And the first iPhone shipping with a powerful graphics chip is a counter to your argument that the future of mobile wasn't clear. The people with the ideas wanted a graphics processor.

The fact that the entire industry apart from Apple (a computer company, not a phone/device company) were completely ignoring 3D exactly shows that it was NOT obvious or clear. After Apple demonstrated the potential it became clear.

Okay, I should have clarify the 'niche' thing 10 years ago was not GPU per se, but of course GPGPU, the GPU as a specialized coprocessor for general purpose computation, not restricted to graphics processing and output.