Hardly any C3 game weights even half of a gigabite. Also at the moment pixel-art stylized games dominate and those take full benefit of nearest sampling which means they have no need to import art of the exact size they're planning to use in the game heavily decreasing their download size.
I didn't see any C3 game with 30-40 soundtracks or very complex sound systems either which would increase download size significantly.
So does CG really needs C3 level of games? If you can just download 200mb games & play it at the best quality without intermediaries?
Plus CG is basically a video. So Pixel-Art likely will lose quality, smooth edges which is not something a pixel-art fan would enjoy. The quickiest solution to that is upscale streamed video specifically for this type of games, but that would mean Pixel-Art games would be even more demanding than AAA games!
That means currently CG is not supporting pixel art. For the real solution, they need to introduce pixellated filter that would be used after video is streamed. With that they could in turn significantly reduce size of the recorded video making Pixel Art games run faster than all other games.
Let's wait until this feature is implemented.