Because many enthusiasts are also sporting 'mainstream' quad cores (Devil's Canyon for example), I think, and the enthusiast platform really is a niche market imo. Wow I took a long time to say that I personally regard 'enthusiasts' seperately and differently than an 'enhusiast platform', if that makes sense? If not, I'll chuck down some coffee
I don't see a mainstream user picking up a K-series i5 or i7, they'll probably go for the lower clocked and cheaper options. So I'd say that enthusiast series start with the K-series up to the E platform (call me stubborn but I keep regarding the E platform as a workstation kinda thingy, not for gamers).
Sure, DX12 is going to more for 6+ cores, but only (!!) if and when devs implement it so how many will do that and how long will it take? It's not like they need it today, it's just extra work and headache it seems to me.
I do wonder a bit, those who are going for X99 now, won't you feel a bit bad when Skylake-E comes out rather soonish? I mean, I often hear people saying that X99 is the stuff to get, but it won't be for
that much longer, it seems. So if you have a good CPU now, wouldn't you rather wait for the next E platform that'll be loads (?) better than the one you're eyeing now?
6.5GHz with 2+ volts? That's unhealthy. But also a very cool clock!