for multiple reasons...

1. Amy's not that quotable.
There's the long "Cool Girl" monologue but it's not that catchy and has zero chance of entering the lexicon like, "The First Rule of (Insert Anything) Club..."

2. Amy's not saying anything new.
The whole hatred of the "Cool Girl" idea is basic. Every girl feels that. Every girl hates that. Except for the fact that they too want the cool girl to be their friend. Which leads to...

3. Amy wasn't cool.
The only person who wants a cool girlfriend more than guys is girls. Guys and girls both wants someone who'll do what they want, cede to their will, and not threaten their position in the friendship. No girl would want Amazing Amy as a friend. I don't think any girl thought, "I wish I was Amazing Amy!" at any point during the movie. And that's because...

4. Amy is a pathetic character.
Amy pretends to be the cool girl and when that fails and her man cheats on her, she becomes the ultimate psycho ex-girlfriend. And the final part of her original plan? Killing herself. She was going to go out with a whimper. She's ultimately wooed back by the guy pretending to love her, which he doesn't, so then she does what she didn't want, have a baby, to trap him into a loveless marriage.
Gone Girl is closer to Fatal Attraction than Basic Instinct. And I just don't know many women who go to parties and quote pyscho ex-girlfriends whose ultimate goal is keeping a man who doesn't love her.

5. I don't think women embrace murderous sociopaths like men do. Fight Club and American Pyscho tapped into a rage that many men feel. Women don't embrace that nearly as much IMO. And, again, the "I'm a psycho ex-girlfriend and proud of it" flag just doesn't seem like one that many women will pick up and start waving.

6. Amy is forgettable.
Maybe some girls will joke to a recently dumped friend that they should go all Amazing Amy on their boyfriend but I doubt this movie has that lasting of an impact. How many girls go out as The Girl with the Dragon Tattoo anymore? I can't see the impact of this film lasting longer than that one.