I guess we can basically sum up by saying that yes, some day a reasonably-priced mid-range card will be able to handle 4K, but that's a few years off.
Of course, what is it with the Metro series? Those games kill systems every time I see a benchmark. I just bought Last Light, and with my 7950 on a 1440p monitor, I get ~20 FPS when I max it out. Bumping everything down one notch makes it much more playable. Granted, the graphics are amazing.
Of course, I don't mean to complain. I'm happy with my card, and I know I have to make compromises sometimes.
AMD FX-8350 Black Edition | ASUS M5A99FX PRO R2.0 | Corsair HX850W | 16 GB Crucial Ballistix DDR3 1866 | Samsung 840 EVO 250 GB SSD | Western Digital Caviar Black 2.0 TB SATA-3 | Samsung DVD +/- RW (SATA) | Gigabyte R9 280X | Cooler Master HAF XM | Dell UltraSharp U2713HM 27" LCD | Logitech MK520 keyboard/mouse combo | Logitech X-540 5.1 speakers | Windows 8.1 Pro x64