How would Dynamic Foveated Rendering with Eye Tracking in games actually work?

I think that ET+FR is still not solved problem because AMD and Nvidia aren’t happy with the idea to reduce gpu requirements an order of magnitude. That is how many generations of gpus? Money to be extracted from pcmasterrace… Sony and Qualcomm may push it tho, Sony to try make PSVR2 wireless, Qualcomm to close huge gap between SoC perf and pc gpu.