One thing that has not been discussed is this...
Alabama is the most talked about and (in)famous college football program in the country. It gets more eyes on it than any other team. Playing at Alabama and winning national championships help make a player, especially a quarterback, very marketable and exponentially increases their "brand" and clout. This can not only help an individual if they have aspirations to play in the NFL, but also for life after football. Greg McElroy is a great example. He was not talented enough to play in the NFL but has spring boarded his career through playing for Alabama and the notoriety, connections, and opportunities it can give you if done correctly. If Ty goes into the NFL draft, he will get much less TV time than if he was returning as the QB at Alabama. It is hard to weigh in this with definitive and accurate numbers, but in today's world of social media, self promotion, and marketing it must be something that a savvy athlete thinks about.