Idealized

Many people complain that comics, movies, tv, etc. all present unrealistic images of men and women. This is very often true, and I'd never disagree with this idea. This concept of using idealized people in stories and art is not new, though; it dates back well into the ancient times (warriors aren't typically as awesome as Achilles, women aren't as beautiful as Cleopatra, no one is as wise as Solomon, and so on). So, if people have been frustrated with unrealistic people in their stories, why do storytellers keep using them?

First off, when going to a movie, who would you rather look at for two hours: a fat, ugly, woman, or a super-model? Purely on a surface level, that answer is obvious. Think of that issue from a director's standpoint, though. The director knows that at any point in their movie, you can walk out and demand your money back. Therefore, it is the director's job to keep the film visually interesting. Nothing is more visually interesting than a beautiful woman. NOTHING.

This is why movies with bad plots will have beautiful women showcased in them (regardless of acting abilities). Either the director knows that the story is stupid, and must distract you from that with muscles and cleavage, or the director doesn't know that and is therefore not skilled at their craft enough to know that a story must have more to it than beautiful people. Either way, you get the same result of a bad movie with hot men and women.

Heroes and heroines most often need to visually stand out from the crowd. This is why in romantic comedies, the two leads are good looking, and the "best friend" roles are cliches in that they don't look as good.

Stories can most definitely have the average everyman, an overweight nerdy girl, or a frail old man as the lead. It's all dependent on the story itself. In character design, the ideal figure is often approached as if it's the basic template of a human. The ideal is the starting point, and afterward the artist adds or subtracts weight (in muscle or body fat), height, physical details (hair, clothing style, tattoos/piercings, etc.) and facial composition.