You are asking about the nature of attraction and it's very complicated. I've been reading about it lately and here's what I have gathered. When looking for someone to spend a life with, women for strong providers and men look for healthy child bearers. This is countered by the fact that we are looking for someone we consider our equals. The icing on the cake is we are looking for someone with similar traits to our parents so we can repair our childhood wounds. That is a summary of 3 chapters in 3 lines. The book I am reading (again) is Getting The Love You Want by Dr Harvile Hendrix. It's very good.
So the reason you've been friend zoned is you don't resemble her parents enough basically... Very very basically. :p
'People are never perfect but love can be. People waste time looking for the perfect lover rather than creating the perfect love' - Princess Leigh-Cheri from Still Life With Woodpecker.