You wont see 4k games on a console, i can guarantee that, there maybe 1 where they do it as a gimmick because there's not much going on on screen.
A single 4k rendertarget would use up all the ESRAM for the screen buffer so any post processing effects and a back buffer would then have to be done in DDR3, meaning additional poor performance, not just what comes with going to a 4k render target.







