I think one obstacle in seeing rookies in the elimination rounds is the fact that this is a very difficult year to be a rookie. In past years, even rookies who built what were essentially running bases (a kit base with kit wheels) could put up some serious defense.
In 2008, for example, as long as a robot was running, it could rack up points for making it around the track. But this competition makes defense difficult with the many possibilities for serious penalties. Unless rookies are especially good, they don't always have a way of getting on the ramp or shooting well.
There will always be good rookie teams in the elimination rounds, but rookies should remember that the first year is a building year. Many veteran teams have veteran knowledge and experience to make better robots and better strategy. Rookies shouldn't get discouraged by this but rather strive to build great programs. And like others have said, it isn't about the number but the performance.
