[Symmetry]

I think you'll find that modern games use many more cores than they used to since mainstream consoles have all moved to being octa-core for the last two generations and you have things like Vulkan better allowing multi-threaded graphics code.

[TakeBlaster16]

Many more cores yes, but 100% CPU usage should still be rare. If your game uses 100% of a 24C/32T processor, it will run poorly on a "mere" 8-core CPU, and most of your target audience won't be able to play it. You're right though, these aren't your grandma's single-threaded games anymore.