For what it's worth I have 150 hours played already on a pretty old system - i5-3570K, 16GB RAM, 1070Ti. I have no idea what framerate I'm getting but I don't remember being bothered by the game's performance even once.

I suspect performance issues are uneven and affect some systems a lot more than others. I also suspect a lot of it comes down to expectations, I'm perfectly happy with my experience but others might consider it "unplayable"!

Edit: I also play offline usually, that might be a factor as well.