Because their wrestlers are consistently mediocre at skills which are teachable and represent pivotal moments in competitive matches or bridging the gap from winning to dominating. Examples include, front head/head under chest, mat returns, getting off bottom...these are things many programs do solidly up and down their lineups.
The also have a tendency for guys to peak really early. Myles Martin, Nathan Tomasello and Bo Jordan are examples of guys who made the gains you make from acclimating to the intensity and physicality of a college room, and then didn't grow or regressed.
They also have more weight cuts seem to turn public than most programs. (Sasso, Snyder, Moore). The following shocks me so badly I've gone back to make sure its real a few times, in Stieber's Flo film, he says when he was a freshmen that he used to skip practice because he felt like garbage and would just float off the last few pounds. That's incompetent.