It's easy to be misled by the tech sites. They are totally dependent on advertising and shopping, so it's not surprising that they hype the new shiny. But as far as games are concerned, the return on investment in cores is
terrible.
Looking at for instance techpowerup.com tests of the latest CPUs, (
link to 10600K test), where they set the 10600K to 100%, using an RTX2080Ti graphics card, we find at 1280x720
3300x - 85.3%
3600x - 87.6%
3700x - 89.6%
3900x - 92.4%
note that the scaling by core is exaggerated by the higher end models having higher boost clocks (and power consumption). At ISO clocks the differences would have been effectively zero, as the scaling we see here is below clock scaling (!). As it would, of course, the instant the GPU would start to affect performance at all. (2080ti at 1280x720 is hardly a realistic scenario for anyone).
The benefit of increasing core count for gaming is completely negligible.
I expect that it will be nigh on impossible for me to buy a 5nm CPU in a couple of years with less than eight cores because as you point out, single thread performance isn't likely to evolve particularly fast in this segment of processors in the future, which simply means that it's an aspect of system building that is becoming a complete non-issue as we have moved from two to four and now further up in "standard" core count.
I see forum warriors blaming "lazy developers" for this, but that's just ignorance talking. Of course the entire industry isn't incompetent, and they have had really good reason to push multithreading as far as they could with the atrocious CPUs of the current console generation. The above is the result of their efforts.