Sex Sells, But Not in the Movies

I was flipping channels last night and came across FOX news.  It was two women and a guy discussing the fact that, although sex sells, the top ten blockbuster movies are practically devoid of sex scenes (or the scenes are subtle and overshadowed by the actual storyline.)  Take these titles for instance:

Avatar
Titanic
Forest Gump
Lord of the Rings
The Godfather
Star Wars
Raiders of the Lost Ark
Pirates of the Caribbean
Harry Potter films
Jurassic Park
Spiderman
Shrek
The Dark Knight

Since erotic romances and erotica are currently the hottest selling ebooks, isn't it odd that sex has no bearing in the mainstream movie industry?