When you look at the hardware included in the "next-gen" consoles, it becomes clear that they're most equivalent to mid-tier PC parts. They're NOT supercomputers. The thing people like about consoles is the predictable, consistent frame rates expected from title to title. You don't have to worry about changing settings to make a game playable. But, on the flip side, you usually don't even have that option. High-end gaming, graphics-wise, is still some sort of PC gaming. As PCs, Macs are quickly getting closer to parity in terms of performance to Windows machines. However, like consoles, Macs have hardware that is largely baked-in and non-upgradeable. Hopefully, external Thunderbolt graphics options will change that, but it's still a work in progress. OpenGL in Mavericks is at the closest to parity on Windows that we've EVER had, and that is exciting.
So, as late-2012 21.5" iMac owner with the GeForce GT 650M AND a performance-minded Mac gamer (OSX exclusively), I play almost exclusively in 1080p - like in next-gen consoles - and I'm having a ball.