> 1. there's a trade-off between graphics/sound quality and story complexity. The better quality your voiced dialogue is - the more you have to pay for every additional line - so you tend to shorten it. Same with graphics - it's one thing to paint 8 frames of 32x32 sprites. It's another to motion-capture, model, texture, and process 100s of different versions of each character animations.

There's another reason for this beyond those practical limitations. The imaginary world that these games inhabit isn't more or less complex depending on the bit depth of each pixel. The difference is made up by the player's own imagination. There's a tradeoff in the space of possibilities of what something could be -- if you give the player more data (better resolution, animations, whatever), then they're more constrained and less free to imagine their own version. One or the other isn't strictly better; stunning visuals provide one kind of value, uncertainty and suspense and filling in the blanks can bring another sort of value. (And both can destroy their own sources of value -- a high-definition but cartoonish boss image or animation can ruin the mood just as much as a botched reveal of some mysterious aspect of the setting.)