For those that missed my re-tweets earlier in the week (@MichaelLarabel), John Carmack tweeted that "I heard [the Rage game] ran fine under Wine. No plans for a native linux client." This was a big disappointment that the head of id Software says they aren't working on a native Linux client for their inaugural id Tech 5 game for Linux.
Carmack later tweeted, "I would be happy to have a native linux client, but someone here at id would need to step up and volunteer to do it."
Unfortunately, with Timothee Bessett having left id Software in January, they no longer have any really Linux-focused developers that I'm aware of. Timothee was responsible for many of id's previous Linux game client and server ports to Linux like Doom 3 and Enemy Territory: Quake Wars.
We've known that the Rage client wouldn't soon be coming to Linux, but it looked like it could arrive in 2012, though now that's certainly up in the air since it comes down to any id Software developers interested in finding the time to port the OpenGL title over to Linux.
At the moment, Rage is still the only game using the id Tech 5 engine while still forthcoming is Doom 4. The worst-case scenario for a native Linux port outside of using Wine would be waiting for the id Tech 5 source-code to be publicly released (at last comment, there's still plans to eventually open-source the game engine just as was done with id Tech 4 and its predecessors), but that will take the better part of a decade at least. Even the current open-source id Tech 4 efforts aren't particularly active.
As id Software and Epic Games change course, at least now there's other major game studios pursuing Linux gaming opportunities. Separate from anything Valve related, Canonical has also worked out a gaming deal that's forthcoming. It's "a major game publisher, arguably the largest, and they
will be distributing some titles to and through Ubuntu in the coming year." Hopefully more details about that will be publicly learned in just over one week at the Ubuntu Developer Summit in Oakland.