People have been saying that for 5 years (which is, in fact, how long XB1/PS4 have been on the market). Single-threaded performance is still the dominant factor in gaming 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.