Because they were probably given some sense of promised playing time when Mullen was in control. It's been widely discussed how often Mullen would not start the better players.
Go look at AR-15, Pierce, etc.....Was Copeland really deserving his spot? Do you think we didn't have a more reliable wr?
Plus, a sports journalist reported how our practices were lacking discipline and seriousness compared to other programs. He said the players acted better than what they were.
Mullen had a culture that was very lax and, at times, immature(go look at how they refused to stay behind for tradition after a game, besides one player).
Frankly, it's possible that we are weeding out the Mullen recruits that we don't need.