To the best of my knowledge, it's really hard to program games to take meaningful advantage of multiple cores. They're by and large by nature single-threaded workloads, and there's only so much you can do to spread the burden among multiple threads, so single core speed is more important for games than number of cores, which is why Intel's processors, for a good while prior to Ryzen, were better than AMD's for gaming, which were good for multi-threaded applications but had poor single thread performance.
Also, my perspective is that of one who games at 60 FPS, not one who pushes for the absolute highest number of frames possible.
while that is true and for a very long time the fast quad core or even a dual core was all you needed
times do change and things are progressing faster .
for almost 10 years (2008 to 2017) intels flagship gaming processor always had just 4 cores and 8 threads ,
but then in 2017 intels flagship and the best gaming cpu on the market i7 7700K (released in q1/2017)
became outdated by the end of that same year and get surpassed by 8700K (released in q4/2017) ...
furthermore 7700K essentially gets relagated into an i3 processor performance territory
in just a 3 years time (with the release of 4c/8t i3 10100)
7700K was the last flagship quad core cpu and the relic of a dying era
with no real progress in cpu performance .
all it took was a good competition presented by AMDs ryzen processors ...
strong single core performance is still very important today
(fast 6 core will perform better in vast majority of games compared to slower 8 core)
but there are a lot of games that can utilize more than 4 threads these days .
dual core cpus are pretty much obsolete at this point as are older quad cores (with no hyperthreading) .
you can still get away with a modern 4c/8t cpu (i3 13100/14100) for entry level gaming ,
but if you want to have really smooth experience
you need at least 5600x or 7600x which are 6c/12t processors
(13th and 14th gen i5s with locked multiplier are not so great so ideally i5K as an alternative) .
while the best gaming cpus on the market today are 8c/16t X3D amd chips 5800/7800/9800 X3D .
so to sumarize in just 8 years the core/thread count of the flagship gaming cpus doubled
while in the previous decade it remained completely static ...
60fps is no longer a good standard either (if you are going to build a brand new system) ,
even for entry level systems you can buy 120/144Hz full-hd monitor
for a 100 bucks these days , so getting some extra frames and getting closer to 100 average FPS
(here your graphics card play the most important role of course)
and even more importantly also getting decent 1% lows in cpu heavy locations never hurts ...