Intel were originally planning 10c max (and 44 pci-e lanes) for Skylake-X.
There is a 12C version of that slide as well i belive, the thing is, if they in fact limited LGA2066 to 10C, the max LCC die, what whould have happen to the other part of HEDT sales that is Workstations? They sell 2011-3 Workstations up to 22C with Broadwell-E, the entire Xeon E5 V4 lineup.
They cant do what they used to do on Broadwell-E and lower. on that aspect SKL-X whould have been a massive regresion over BDW-E.