No exactly sure what you're getting at all_the_colors, however, if you're someone's friend for a longer period of time, feelings of becoming something more rarely happen. They see you as one way and it usually doesn't change unless one of you changes in certain ways. For example, did you ever have a female friend that you couldn't have for more yet after not seeing each other for years, you meet her again and all of a sudden there's a lot of interest there?
People get a perception of you and they either like you as a friend or more, usually within a short span. If you're seeing yourself in that "friend zone" so much, and you want something more, you should make that clear earlier on, otherwise it likely won't happen.
-to be nobody but yourself in a world which is doing its best, night and day, to make you everybody else means to fight the hardest battle which any human being can fight; and never stop fighting.- e.e.cummings