We want what we can't have. During the Victorian era, sex was the unmentionable, so everything was a metaphor for sex. By now we're so bored and jaded that sex is a metaphor for everything else. People won't watch movies, read magazines or even drink sodas unless they're dripping, so to speak, with eroticism. Ring, ring the next generation of phone sex.
Eroticism depends on objectification, traditionally of women.
Often, we consider the seduction of a beautiful woman to be the ultimate sign of success. This has led some theorists to suggest that masculine desire is actually a kind of homosocial desire. Certainly what we find attractive is determined by the gaze of the other. The argument that these things somehow emphasize reproductive characteristics is ridiculous, as any glance at a 100-pound model will tell you. They're attractive because they make women weak and dependent on men.