If she had done that Billboards performance back in 2008, her career would be very different rn.
Its crazy to think that back then she and Bey were on equal levels (Circus actually debuting with higher than IASF I believe, and they were the two biggest females that year) but their careers went in two different directions in the eras after. I won't deny that Britney is iconic but her half-assing her last 2 eras kinda put a damper on her brand.
Hopefully her new era will reignite something but its been almost 10 years since her "comeback" and with all these new young girls out, its much harder for her to compete.