Texas chose to ride with a superstar player for the entire season. They came within 50 minutes of game time from pulling it off. Texas wins that game 45-20 or something if Colt stays healthy. Alabama wasn't built to play our type of offense (it won A&M a Heisman later).
I'm sure Alabama suffered their own critical injuries throughout the season. You play the game with the team you have. While it was the ugliest of bad beats, backup QB was the weak link, and it broke there.