Yeah I think it's a case that female vocals maybe don't have the same range or deep quality that's needed for when trying to sing over a bass, guitar and drums.
Of female singers though, some female singer songwritersare my favourite singers. Lisa Hannigan that sings with Damien Rice has a fantastic voice. My favourite overall is Gemma Hayes. Her voice is incredible.
YouTube - Gemma Hayes -Ran For Miles - Live At Abbey Road