Sadly, I can't find anything to prove my point, haha. But I'm sure that when I built my current PC ~5 years ago AMD had a better overall performance for their price than Intel, especially when using all cores (but they used hexascores, when Intel still used quadcores). I'm not saying that they have the same performance in their top-level models, of course. But they are in the 1000€ region, which is way too high imo..
Edit: And one more thing: It's not really the way that you can just put in more cores and consistently increase the speed with each core, but you probably know that