Lets say you can split up your threads to AI, Physics, Rendering, Networking, etc. etc. But lets say Physics dominates: then your game is still single-threaded bound. You only get faster if you make your physics faster.
You can split your game up into work-queues, thread pools, and such. Except not everyone is up-to-date with the latest techniques yet. Furthermore, thread-pools aren't always cache friendly and may hamper your performance. (If Core1 works on something, then Core4 completes the work, you have to transfer all the data out of your L1 and L2 cache to continue working on it on Core4).
So its not exactly an easy thing to program.
But many games are still single-thread bound (despite being multithreaded). As such, Gamers should still prefer single-thread performance.
Games make use of up to 6 threads, but single-threaded performance still determines overall framerate to a large extent. Games are not exempt from Amdahl's law: as long as you've got enough threads to offload work, it comes down to the single-threaded portion of the workload. The faster you can run the main game loop the faster the game runs.
Gamer's who prefer cutting edge performance should prefer multi-thread performance.
Optimizing for MT-heavy games is the gaming equivalent of premature optimization - everybody can run Doom at a million FPS, but Fallout 4 or PUBG shit all over every system and you'll be begging for every frame you can get.
You can "prefer" whatever you want but developers don't care. This site of all places knows that time-to-market is what really matters. If you want to play those titles, you have to deal with it. Either optimize for the shitty titles, accept that you're going to be losing a fairly significant amount of frames (the 2700X is behind as much as 30% in some titles), or don't play those titles.
I mean that if the software is implemented in the correct manner, "more can be done" by utilizing multiple threads.
That's because once you are down the critical path, the only way to go faster is by improving single core performance.
There is a reason reason why Core i5 are so popular with gamers. They have just enough cores not to limit a game engine, excellent single-thread performance, and they are affordable.