Radiohead is one of the most influential rock bands of the 1990s. The English speaking world is the biggest music market and the most wide known world's music arts come from the English speaking world.
Xuxa comes from a peripheric country. She is a super star only in Brazil. She is famous only in the Iberian language countries. She had a TV program in the US in 1993, but she never became a celebrity there.
Eventhough, according to BSA, Radiohead sold 21.4M records
(
https://bestsellingalbums.org/artist/10736 ) and Xuxa sold 19.4M records (
https://bestsellingalbums.org/artist/14360 ). Not too different numbers. Brazilian population is very big, but not only in Brazil Xuxa sold more records than Radiohead, but also in Argentina and Spain.
Of course, influence on arts doesn't depend only on the number of sales. Radiohead had a much bigger impact on the music. On the other hand, music was not the most important Xuxa's activity. She was a singer, but she became a celebrity because she was a presenter of TV shows (and she was also an actress).
https://en.wikipedia.org/wiki/Radioheadhttps://en.wikipedia.org/wiki/Xuxa
