Yeah I hear you on that. I don't know the whole history of Intel or how they decide when to release new chips, I could say the same about Nvidea.
To be honest it's a bit frustrating because for example in my case, when I put my Skylake (6th gen) together I figured there's no way they would release a new chip. But they did, 2 cpu's that do not have motherboard compatibility. I sure as hell would be mad If i actually waited out for Kaby Lake then another same socket but different chipset comes out in less than a year. This is where I'll bring in Nvidia.
The 10 series, 1060 1070 1080. I don't remember the details but people who bought the Titan X pretty much got a good smack in the face when the 1080ti was released for substantially less (40% or so). I think it was released 6 months after. Then a Titan XP was released with 7-8% improved performance over the 1080ti the next month.. lol I have no clue..