True. That said, he was also helped by the fact that he seemingly had the state of Texas to himself for a long period of time. Texas A&M was trending down but refused to part with Slocum. Baylor was just awful, and Texas Tech was running a gimmicky offense. The only players that I ever saw Mack lose out on between 1999 and 2009 were Adrian Peterson and Ryan Perriloux. I also remember that Texas would have its junior day in March and April, and basically got oral commitments from almost its entire future class that weekend. It didn't seem like he had very much competition.
Once Baylor began to become competitive and LSU started to expand its recruiting tendrils into Texas (helped by all of the Louisiana relocations after Katrina) it became more difficult towards the end. Here are his recruiting rankings over the last five years:
2010: #3 (2 five stars, 19 four stars)
2011: #3 (1 five star, 15 four stars)
2012: #2 (2 five stars, 15 four stars)
2013: #24 (0 five stars, 9 four stars)
2014: #20 (0 five stars, 6 four stars)