It takes a couple years to develop players especially when you don't have 4 and 5 star guys. Last year because they had so many blowout wins they were able to give backups reps. Guys way down the depth chart as many reps. BYU graduated a lot of talented players. The next guy up were pretty good, but the guys behind them have very little experience.
And remember this team is acutally very very young on both sides of the ball.