Free college education: check.
Get National Championship ring: check.
Play for the most storied college football program around: check.
Learn from one of the best ever (CNS): check.
Hold clipboard for 5 years: where do I sign up?
You are correct, from a "Bama fan" perspective, but remember many of these kids didn't grow up being fans and they were just recruited by Bama, which is a huge compliment.
However, at this level, even for the 3 star guys, they believe they are good enough to play and if they see the writing on the wall and figure out that they might not be good enough to play at Bama or some other big school they probably still feel like they need to maximize the opportunity for playing time at some other schoool.
I know we'd like to see them stick to their original commitment, but how many times does the guy that holds the clip board for the first 3 or 4 years finally get his opportunity to be a star his last year or two??? It happens, and it may happen at Bama this year for BS, but with today's player development at the high school and camp level, most of the elite guys are ready to play after 1 redshirt year, some even as TF.