Why is it Hollywood has never had a leading Black female heroine in movies?

The only "Black" females they have had are clearly MIXED RACE females, with light skin and very caucasian features.......Does this tell us that Black female beauty is only seen as beautiful and appealing when it mimics White female beauty.......which in that case, it is not really Black female beauty at all.....but rather the "White Factor" is a must as a mix.