To answer the OP's original question... Yes. She is the only female artist to have Top 5 hits in each of the last 4 decades.
However, she is also the 1st female artist to have #1 albums in each of the past 4 decades, until Madonna 2 years later.
If she has a #1 with any of her new singles this year, she'll also be the only female artist again to have #1 singles in each of the past 4 decades. With only Madonna able to catch her.