As the shaders are basically only good for post-processing whatever output you get from your renderer, you'd definitely need to use an infinicity-esque approach for everything interactive in a game, but you could still leverage shaders in conjunction with that for non-interactive stuff like weather effects, animals (birds flying around etc), pedestrian and vehicle traffic and so on
I suppose you could use the technique to render a backdrop (either by rendering to a texture or by rendering it first, although you’d end up with a lot of overdraw if not careful) and then use a traditional renderer for the foreground. Not sure if it would win you anything, but certainly possible.
Could you also upload dynamic object data as VBO’s or uniform arrays or something and read that in your single-shader-renderer? Still likely not worthwhile, but a fun possibility perhaps.
I guess that’s not unlike what jheriko said above.
