Pre-casting

This topic gets my blood boiling!! A veery controversial topic. I find nothing worse than going to an auditon, trying your hardest, doing a great audition, only to find out (or not which is most often the case!) that someone already has that part! I think it is fair to say that Director's need to have enough people in mind in order to cast a play (or else there would be no point in performing it), however, these should be suggestions only, and not then develop a closed mind to other possibilities, or new people that happen to audition for the part/s. At a theatre where I have been a member for a couple of years, there is a standard unspoken rule, that there are certain directors who you don't bother to audition for, because they have a completely closed mind! What upsets me is, how does a new person entering into a theatre group to get cast in a play, if they won't be looked at as a possiblity? In my case, I have had 20 years experience in amateur theatre, and have not been able to prove myself, because some groups don't even do one-act plays, so there is no forum to display your talent. I think it is a shame, that to get into a play, I have to travel all over the metro area to audition, because the theatres that are close to me really want proven talent in their shows!
What do others think?
Just thought I would prompt a little debate/discussion on a topic which is close to my heart.
Chris.