The highest average recruiting class of any champion in the last ten years was Auburn. They had an average of 15. But they were carried by Cam Newton, the best JUCO signee maybe of all time.
Every other champion in the last 10 years had a top-3 recruiting class in the 4 years prior to a championship, and 2007 LSU was the only team without 2 top-3 classes
If you sign 4 straight top-10 classes and get a couple top-5 in there, you WILL compete for a national title
You just can't out coach talent like Alabama has.