The reason was the Georgia defense. Giving up long run after long run didn't help either, and do we really need to discuss their special teams? Also Oklahoma didn't put together 4 solid quarters of football at any point during the season. The answer to the question is Bama now that they have 3 of their 4 linebackers back.
What Oklahoma did down the stretch would be on par with the 1990's Bulls keeping the ball out of MJ's hands and putting it into Pippen's hands for the final five minutes. Lincoln Riley kept the ball out of Mayfield's hands down the stretch and blew 3 separate possessions to win the game. 3 chances to win the game and 3 failures because OU went run, run, run, run, run, run, run, run, run, run, run, run, run. OU was there because of BAKER MAYFIELD, always put the ball in your best players hands at the end of a game. Lincoln Riley decided MJ wasn't a good option and Pippen was the best option. Pat Riley, Phil Jackson, etc where all bug eyed watching those ridiculous play calls out of Lincoln Riley down the stretch.