They were popular on AMD because the other options were spotty at best. I loved my SiS 735 and ULI M1695 boards, but virtually nobody touched the chipsets-- almost exclusively second tier manufacturers. VIA was the leader before nVidia hit, but they had a long string of half-baked launches... you had to assume that you'd wait for the second-revision chipset.
On the Intel side, the only place they competed was in a specific enthusiast gamer segment. The nForce 780i chipset was hot running and unpopular, but people bought it because they wanted to run SLI. I srtill have one sitting around, from a "gaming PC" I fished out of a dustbin The heatsink on the chipset is comically large and cries out for a fan.
It also would allow AMD to potentially gain an edge over NVidia in the GPGPU space. Missed opportunity imo, it still seems like an excellent idea.
That said, they have been working on opening up the GPU space via ROCm: https://rocm.github.io