Britney is an icon, not yet a legend. She needs to slay once more.
Icons become legends by overcoming adversity.
For Whitney is was crack and Bobby.
For Michael it was child sex abuse
For Madonna it's her terrible voice ( ) and the sex book scandal.
For Britney, it's her mental insanity, like with Mariah.
Britney is viewed as a joke. It would be a stretch saying she's an icon, but she is nowhere near a legend. She's always been a label puppet, and will remain that way until the end of her career.