Why such a big gulf between your confidence for cinema and your confidence for video games?
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.
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.