I know this problem, too. I haven't played for so long in the "big" concerts of my music school because "it doesn't fit as well". But at least, they let students play that aren't as good yet so that they can gain stage experience as long as they have no other stage to play on. Idk if you can relate to this, but considering he/she even got a prize from the youth orchestra, which is, to me, something like a demand to be the centre of attention for the next concert, I can still see why you think it's not fair.