Most of the advice before me is good advice. Here is my 2 cents.
As a father with two high school dancers that have danced since age 3 - one daughter just shows up. The other daughter practices before dance class and then practices after dance class.
The daughter that just shows up - she's tired of dance and does not want to dance after high school. She goes to see her friends at dance, gets to perform on stage, and gets to go on road trips and sleep overs with those friends. She's in it for the friends and fun.
Dance teachers have tried to motivate her more - to no avail. She doesn't want to put anything more into something where she sees no additional return.
The other daughter loves dance. She would walk five miles to dance practice if I did not give her a ride. She'd probably dance the whole walk to dance practice. :-)
My daughter that loves dance is in high school now and loves high school dance. She is forced to do everything - pick the theme of the dance, choreograph the dance, teach lessor dancers how to dance and perform, pick and edit music, etc. Plus my daughter that loves dancing is able to be a teaching assistant at the dance studio. All of this is teaching them leadership skills.
At some point they have to want it. You cannot want it for them.
You can try putting her into a more competitive studio. Over the summer send her to some intensive dance camps that will challenge her more. Buy her some advanced technique DVDs. Those should shake her up and make her realize - she is a big fish in a small pond. If you she really loves it - she'll pick up and run with it. Otherwise, she's just enjoying her childhood and friends.
There are lots of major regional dance competitions all over the country - almost every weekend. Usually the bigger the city - the better the competition. Look for competitions:
You will see the top talent (by age group and type of dance) and the top dance studios.
Problem with kids today - they think they can do everything perfectly - without practicing. So have your daughter start doing solos and entering these major regional competitions. If she loves it - keep on doing it. If she misses her friends then she does not love dance.
You cannot make someone (even a daughter) love something.