when the dolls hit the shelves

when the dolls hit the shelves

When commenting on the popularity of some celebrities, someone says that,
"When the dolls hit the shelves, their fifteen minutes of fame are over."

What does this sentence mean?

"Celebrity dolls" like these: www.i-am-bored.com

When an entertainer, or whatever, is so popular that he or she gets a celebrity doll, there will be a backlash. People will get tired of seeing that person and go on to the next big thing.

Thanks!