It's flat out wrong to assume its going to happen. Intel has killed $50 discrete, because these were rubbish to start with, the dies are tiny and the TDP is low. It can be matched by a iGPU easily because iGPU have similar specs.
If Intel wants to compete with mainstream cards with 125W TDP, or approaching mid-range with 200W TDP, they are going to have to start releasing monster APU dies >400mm2 and a TDP of 200W+ combined.
Sure, it can happen, but then it won't be CHEAP.. thus, it wont have the volumes to threaten anything.
tldr: Intel doesn't do magic, perf/mm2 and perf/w still is the defining factor to determine whether Intel can threaten a certain market of discrete GPU or not.