Assume you have two players vying for a starting job during camp. One has better natural physical talents and consistently performs better in various drills. The other isn't as talented but certainly has D1 starter attributes and consistently performs better in live scrimmages. This pattern presents itself early in camp and is consistent throughout. Which player do you choose?
For me, the answer is obvious - you go with the guy who plays best in the situations closest to a real game, even though the other guy would get a much higher rating if they were HS recruits being evaluated at a t-shirt camp. I bet this situation happens much more often then we're aware, and probably answers the question of why Joe ends up starting 'lesser talented' upper classmen more often than some would like.
I'll try a poll: