Mmm... I am nearly sure that this is FinFet's doing.
Intel can't deliver ungodly chips like SB or IV or even Haswell. Their Broadwell E can't OC more than 4.5 Ghz and Skylake can't go past 4.9 Ghz while SB can go 5.2 Ghz on air and IB and even HW can reach 5.0 Ghz...
nVIDIA can't scale down (so no sub GP 104) for a time and their graphic chips despite are decen't OCers can't past 2.5 Ghz
AMD chips are being delayed and Polaris 10 only manages 390X levels at best and seems that can't OC more.
As for VIA, they might come at 2017, so is time to wait there.
And as for ARM... they are still good, but definately needs more improvements.
In few words FinFet ended to be a sidegrade instead a massive upgrade. A lackluster improvement that needs more fixing than other things.
So definately according to this thread:
The true upgrade will be EUV.