I don't agree with this.
On the highest mainstream I7 CPU's - more and more of the die is dedicated to an IGPU that is completely pointless for the vast majority of users buying that mainstream I7 CPU.
Intel could instead make the top mainstream I7 CPU have no IGPU, and dedicate much more of the die to additional CPU cores.
Instead, they continue to dedicate more and more of the die to the IGPU - give it another 2 or 3 generations and god knows how large the IGPU will be.
This is almost forcing people onto the HEDT x99 platform, whether they like it or not, which commands a significant premium over Z97/Z170. You have to buy 4 DIMMS for the quad channel memory (to take full advantage of it at least), the X99 motherboards command a significant premium over the mainstream motherboards, etc.
There is no reason other than profit margins, for the top mainstream I7 to have such a large proportion of the die dedicated to a 'useless' feature for many.