The obvious answer would be "offline rendering".
Even if the non-interactivity of pre-rendered video weren't an issue, games as a category can't afford to pre-render more than the occasional cutscene here or there: a typical modern game is much longer than a typical modern movie -- typically by at least one order of magnitude, i.e. 15 to 20 hours of gameplay, and the storyline often branches as well. In terms of dollars grossed per hours rendered, games simply can't afford to keep up. Thus, the rise of real-time hardware 3D rendering in both PC gaming and console gaming.
Rendering is not the problem. I would say that the uncanny valley has already been passed for static images rendered in real time by current 3D hardware (this NVIDIA demo from 2007 gets pretty close). The challenge for video games to cross the uncanny valley is now mostly in the realm of animation. Video game cutscenes rendered in real time will probably cross the uncanny valley with precanned animations in the next console generation but doing so for procedural animations is very much an unsolved problem.
(I'm a graphics programmer in the video games industry so I'm fairly familiar with the current state of the art).
I would like to propose this as a thread for people to write in their predictions for the next year and the next decade, when practical with probabilities attached. I'll probably make some in the comments.