Which sort of didn't happen for games, most games actually have a similar CPU load as DF, with one thread that taxing 100% of a CPU core and a few more sitting well below there (physics rendering beside).
A lot of game engines are three or less "main" threads thanks to the xbox 360, which effectively has a hyperthreaded tri-core cpu. It just wasn't worth redesigning for mass-threading when you could offload rendering and physics to other threads and use up all the available cpu power in the console. The PS3 was unhelpful in this regard also, despite being effectively an 8 core CPU its weird split architechture meant that code written for it wasn't ported to PC.
This is changing now, with the new consoles out the big AAA cross-platform game engines will restructure themselves to use 8 cores, as that's what both the XBOne and the PS4 have.
Incidentally they also both have an APU architecture, so I wouldn't discount APUs from PCs just yet, the high-end AMD APUs are already on par with the consoles (no surprise given the consoles contain AMD APUs). It wouldn't take much more advancement to render dedicated graphics cards obsolete for everyone except the "extreme" gamers. Graphics cards would go the way of sound cards...