Britney in 2007 had more impact than Bey's entire career
The news channels EXPLODED with her headlines not only in America but in Europe too. There was not one person (teenager or adult) that didn't know of her breakdown.
Apart from this, she's the only artist that was still loved and respected despite the meltdown and terrible things she did to herself. I don't think Bey's image would still be the same after that.