Unfortunately, yes, that's the way the cookie crumbles.
The women in the top row of pictures are pop icons and house hold names. They're more than just record sales and chart stats. They are the legends in the making for this generation of artists.
With the exception of Nicki Minaj, the other chicks in the bottom row are nothing more than successful faces in the music industry that will never be revered as transcendent or potentially legendary no matter what level of success they surmount to.
So unfortunately yes, some artist are below others and it is fair.