But all the "big" titles use direct3d/directx, which will never achieve native speed with wine, so that doesn't really matter. Plus, if the game uses opengl, it's more likely their already is a linux-port around anyway.
Edit: @topic: Well, I'm glad I didn't buy the game. I almost got weak when it was available for only ~20€ for a short time on amazon (not too long after release).
For the reasons: I actually think it's possible that Ryan just wasn't able to pull it off (till now, at least). I mean, porting an AAA-game like UT3 is surely not a simple task, it might have been too much for him even though he's very experienced at it.