The 8700k @ stock gets a 1230 Cinebench r15 score, if we divide 1230 by 6 (the core count) we get 205, that's the score per core. 205 times 8 cores for the new chips is still only 1640, which is about the speed of a 1800x, the new 2700x is scoring 1800+.
Keep in mind Intel is still on 14nm, as they've been for years. This isn't innovation, this is stagnation from a company that hasn't experienced competition in long time.