That was one season
He was only at A&M for 4. From Junction boys going 1-9 to SWC conference champions 2 years later, to National Championship contender in year 4. Also had a heisman winner while he was there. Guess you are right, he really didn't really accomplish anything at A&M.
"The Aggies suffered through a grueling 1-9 initial season which began with the infamous training camp in Junction, Texas. The “survivors” were given the name “Junction Boys.” Two years later, Bryant led the team to the Southwest Conference championship with a 34–21 victory over the University of Texas at Austin. The following year, 1957, Bryant's star back John David Crow won the Heisman Trophy (the only Bryant player to ever earn that award), and the Aggies were in title contention until they lost to the #20 Rice Owls in Houston, amid rumors that Alabama would be going after Bryant"