You don't need a molecule by molecule simulation. It only needs to meet human perceptual resolution, which is much more achievable than the level you're talking about.
In the end, I just think it's more fun to pretend it's all real, whatever that means, especially since I doubt if anything can be done about it otherwise.
Exactly what I blogged recently: "If your children are watching Tom and Jerry, which do you think is more disturbing, the all pervasive violence, or the occasional, over-glamorized, puff of smoke? If either of those are disturbing to you, why don't you just change the goddamn channel like you would if a steamy scene came up, instead of blaming your lack of parental responsibility on the poor animator?"
