The Beatles were great in the 60's but didn't make it for known reasons in the 70's or later.
Prince was great in the 80's but is (in Europe) completely forgotten at least the last 10 years.
Who is able to keep an audience (sometimes a different one) for decades and sell records?
Here is my top 5 of non-prog Top Artists:
1. Madonna
She is the queen. She has changed her music style so often and kept at the top since Holdiay in the 80's.
2. Queen
Although it has stopped for some years Queen is the band that was at the top from the 70's, in the 80's and in the 90's.
3. Michael Jackson
Jacko was at the top with the Jansons Five and stayed there at least untill the 90's. He will keep his faithfull audience probably untill he dies, despite the fact that his music career is suffering some problems now.
4. Phil Collins
You cannot count the Genesis period from the 70's as The Top, but PC really started at the top with hits like Follow You, Follow Me and Mama and continued to stay there with his solocarreer at least up till now.
5. U2
The only band who stayed with their style, but with slight changes managed to stay at the top.
Who did I forget?