Also, keep in mind how little of the modern CPU's die space is actually dedicated to the traditional cores. A quad-core skylake processor dedicates over half it

Also, keep in mind how little of the modern CPU's die space is actually dedicated to the traditional cores. A quad-core skylake processor dedicates over half its space to things other than CPU cores [1], and that each core itself has a lot of space needed for paths that are always going to be used, like instruction decoding and storing the registers. So gating in a situation like this is only ever going to turn off a very small bit of the processor. [1] http://www.techpowerup.com/img/15-08-18/77a.jpg http://www.techpowerup.com/img/15-08-18/77a.jpg