I think the reason PCs haven't offloaded AI yet is because you have the CPU which can handle all the AI and the GPU does all the graphics processing. This means you can max out the CPU AI (note: not saying this would be as good as cloud AI!) while not impacting graphics at all - not the same for a console (well not quite the same).
Well, it's true that right now, on the PC, it's the CPU that bottlenecks most high end GPUs. We also have to remember though that the PC has other tasks going on in the BG as well when you play a game, unless you close everything which I never do. Sometimes I'd be playing a game and have VMs running in the background as well plus all the apps I have open.