I really doubt the veracity of this report. I mean, Britney was a 19-year-old dancer when "Slave" came out. Taylor is a 28-year-old woman who has never been able to master a single dance move. For comparison:
she might be considered as a pioneer of the kind of pop performances/videos we got to see in the following years after she came out in the 80's, and even at the time. I can tell you, that for example in Mexico everyone was copying her style, from her looks to her dancing and everything, and of course she was influential in the States as well.
There were other girls too, but, I'm not sure if Madonna was the first of them all, or if it was just because she was white that she got all the credit.
I'm not a big fan of Maodonna, but I recognize even when I was a kid, in the 90's, 2000's, she was still a big figure in the music industry, she kept releasing hits and great videoclips, almost 20 years into her career. Then in the late 2000's she reinvented herself. Probably I think she's flopping in terms of popularity although she keeps selling her tours, and she becomes more desperate each day to stay controversial and current, but the legacy is still there. I mean, she doesn't need to do anything anymore and she'll never lose her recognition from the GP.
I think she was mainly known for her change of style between eras, or even during the same eras. She and Michael are considered the queen and king of pop, among other things, because they created what we know as "iconic outfits", "iconic performances", "iconic videos". Britney is considered part of that royalty because she was doing basically the same during her prime. Others tried as well, but not everyone had the same success.
I love Britney, but Madonna, sweetie, I'm so sorry...
Anyway, get educated: