I have heard some say that 8 cores will be required for future games.
I have yet to see such an assertion coming from a knowledgeable source like a game developer.
I think that is FUD perpetuated by AMD.
Game developers want the largest possible market for their games.
No game developer will willingly undertake the extra cost to make their game multi core enabled and also require many cores to run.
They would not sell many games.
But... OH you say, I see activity on all 8 threads.
Be careful how you interpret task manager cpu utilizations.
Windows will spread the activity of a single thread over all available threads.
So, if you had a game that was single threaded and cpu bound, it would show up on a quad core processor as 25%
utilization across all 4 threads.
leading you to think your bottleneck was elsewhere.
It turns our that few games can usefully use more than 2-3 threads.
How can you tell how well threaded your games or apps are?
One way is to disable one thread and see how you do.
You can do this in the windows msconfig boot advanced options option.
You will need to reboot for the change to take effect. Set the number of processors to less than you have.
This will tell you how sensitive your games are to the benefits of many threads.
If you see little difference, it tells you that you will not benefit from more cores.
Likely, a better clock rate will be more important.
Many threads are good for an app such as editing that can really use them.
Even then, single thread speed counts.
Read about "Amdahl's law.
https://en.wikipedia.org/wiki/Amdahl%27s_law
I think threadripper is coming up against this phenomenon.