So you buy a 8700K because it's 0,4% faster than a 8600K?
And no, the 9900K will not be the fastest gaming CPU for sure. Quote me later.
So you say most of the PC gamers are beyond the 60 Hz displays. You are absolutely NOT right.
Saying that 9900K/9700K in 3K-4K gaming shows how absolutely "unprofessional" you are. Unprofessionality is also shown by the fact that you buy the most expensive consumer CPU and don't buy a more balanced config. You say and have a 780 Ti paired with the 8700K, and speak of 165-200 Hz gaming, really?
They will get maximum the same, the 9900K likely worse performance than a 8700K in games.
Nobody cares how many cores AMD needs to get a better multithread CPU than Intel if it's cheaper than an Intel with less cores. And in terms of single core performance, Intel's lead reduced to around 10% with the fastest GPU. A pure fanboy you are. Fact.
Against the 8400, you have the 2600 for the same price with better CPU performance. And CL Pentiums are a piece of crap for that price. 2 core CPUs? Meh.
Panicking is meant in the way that they raised core count after the release and success of Zen. Yep, I know, they didn't make CL in half a year, but you should be aware that their engineers knew what Zen will be capable of and a simple usual frequency boost as in the last 3-4 generations won't be enough. That's why they released higher core count CPUs, and raise it again in their next gen CPUs.