They haven't had anyone to contribute at the NHL level because the high end guys they've drafted have only been in the organization since 09. They're also stuck behind guys who have earned a spot. I don't see why you think this = fail.
Again, I still don't see how that means we've failed at developing them. It's not failing if the oldest guy who hasn't made the NHL is 22. It means the book is still open.
Shero only had 4 or 5 D picks, who have played in the organization at any level, before 2009. Sneep, Strait, Bortuzzo, Grant, D'Agostino. Of those, 2 were traded for picks, 1 was waived and is now an NHL d-man because we had no room... The other just finished his senior year at Cornell and is playing in WBS, and the last one is currently on the roster.
I don't get what's wrong with the fact that guys aren't making the NHL at 22. Everyone follows a different path. Doesn't mean they've failed.