First she has 3 CONSECUTIVE ICONIC performances with every album that she releases:
Then she gets acknowledged by the Queen of Pop, Madonna:
Then she does the messiest performance of her career, and yet, it remains iconic as well as the song
and the line "It's Britney, bitch":
After her breakdown and comeback, she goes on The Circus Tour which completely sells out and grosses 131 million
Not to mention that we have ICONIC music videos:
With her amazing career, our Princess of Pop, being 32 years old, earned her place in Las Vegas, which currently seems to be the right thing for her career and her family and makes her on the same level as Elton John, Shania Twain, Celiné Dion and Cher career-wise.