That was kind of my point about being the best at 16 doesn't necessarily translate into anything, not being specific about Donnelly really. Those 10 players who didn't make it weren't all victims of bad management, not being put in the first team etc etc. although there seems to be a big trend of non-progression. I would suggest it is quite common if you look through other season's U16 squads to see who made it.
I remember watching a show about youth football, it was a documentary about Lilleshaw before it was closed. It was a similar situation there. Out of the group of 20 or so lads who moved in at 15 years old, the only one to make it was Alan Smith who actually decided to leave really early because he was homesick.
The only two players I can remember watching in the Victory Shield on sky who went onto big things are Owen and Joe Cole. Surely there are others but I can only remember them.