I honestly think that he is putting way too much emphasis on track due to near-sightednesss and emotional decision making. Think about it this way, he is all ND during the summer while training for football and his senior season, and he is all ND during his senior football season. Then the football season ends and suddenly he is not focused on football all day everyday, and he starts training for track.
He loves track and now all of his focus is on it so that will tend to be the only thing he can think about. Then, after training for track for a few weeks he has to reverse gears and switch to football for a week. This might frustrate him a bit as he really wants to do well in track, and this might throw off his training regiment. So he goes down there to play football when all he can think about is track, and starts to put an overemphasis on track as the main deciding factor for his college choice.
Well what awaits him down there are recruits from all different schools trying to persuade each other to come to their respected institutions, and with Darby already over emphasising track, he is easily persuaded by the recruits from FSU and assorted SEC schools that track is the selling point. After the game, he decides that ND isn't the right institution for him because there weren't any ND guys talking to him because they already assumed he was an ND lock.
Darby seems like a smart kid, but he lets his emotions play into his decision making far too easily. He needs to take a step back and view this process from a logistical standpoint. College recruiters are master communicators and can easily manipulate someone into thinking that their respective schools are the best place for that person to go, whether it be true or not. Darby needs to learn that every recruiter will say whatever they can in order to sell the institution, and that he needs to realize that they are only pushing track because that is all he is thinking about right now.
There is your Darby conspiracy theory for the day.