Perhaps Intel has been secretly working on a totally new architecture to replace "Core". and is waiting for a reason to reveal it (like if Zen captures too much market share)...they have the money to do pure research, and every reason to do so (to stay on top). My thinking is, what have they been doing all this time - surely these little improvements to the existing Core architecture can't be taking up all their people's time - it would be stupid for Intel NOT to have an ace up their sleeve, with all their money and talent...
