If you look at all of the Black women of pop, the majority of them have had light skin or more European features. Are those the only one who have a chance at being an icon?
Whitney Houston and Janet Jackson are two of the most commercially successful Black women ever and neither is light skinned. Not necessarily but there's never been a dark skinned Black woman blow up like that.
It's possible to be darker and have success but most of the time the lighter girls are given more attention by record labels, the public, tv shows, etc. Unfortunately today it is still thought that the more "European" you look ie. white or with white features like smaller nose, lighter hair, etc. the more attractive you are.
there are exceptions to the rule, but Hollywood has always taken a preference towards more light skinned women. This is prevalent in music videos as well as movies.