What software is missing? I figured the AMD G-series CPUs used the same graphics drivers and same codepaths in those drivers for the same (Vega) architecture.

My impression was that it was still the hardware holding things back: Everything but the latest desktop CPUs still using the older Vega architecture. And even those latest desktop CPUs are essentially PS5 chips that got binned out.

Deep OS support for unified memory architectures for one. Things they tried to do with HSA etc. Also NVidia winning so much gpu programming mindshare with Cuda, and OpenCL failing to take off on mobile, dooming followon opencl development plans, didn't help.

In the wider picture, gpu compute in general on PC also failed to become mainstream enough to sway consumer choices. Development experience for GPUs is still crap vs the cpu, the languages are mostly bad, there's massive sw platform fragmentation among os vendors and gpu vendors, driver bugs causing OS crashes left and right, etc.

Re your impression, yes, AMD shifted focus more toward cpu from gpu in their SoCs after a while when their initiatives failed to take off outside consoles. But it's been an ok place to be, just keeping the gpu somewhat ahead of Intel competition and getting some good successes in the cpu side.

iGPU Vega is actually really, really good esp when it comes to perf/watt. It is bottlenecked by the slow memory bandwidth. DDR5 will more or less double iGPU performance.