I know x86 and ARM arent the same thing architecture wise,
but we can all remember the days before big.LITTLE arrived to ARM, where most CPUS were either too slow for their own good or heated up while just browsing on the web, and wasted battery like crazy. And all those things changed when we finally moved into big.LITTLE.
I can't say for certain this might work that well in x86, because dealing with Windows shenanigans sure sounds like trouble, but at some point the core race will have to come to an end and efficiency/power performance will need to improve.
We havent move from Octacore in ARM from a long while ago and neither Apple or Qualcomm seems to be planning to add more cores to devices that are already as fast as they can, and it seems there's still enough room for improvement.
And I think the same thing will start happening in PC. As of right now, Intel has the architecture laid down, but not the core design.
Meanwhile, AMD has the Core design, but the architecture, not so much. They will probably face the TDP wall that Intel found just a while ago. It will be interesting to see which path they will take.