Good points... but I'm not sure if that really helps me rationalize why we couldn't at least get 1 stop in the 2nd, 3rd, or 4th quarters. Just 1 stop... seems like Murray and their O converted every friggin 3rd down they needed. An another data point... Army shut down Oklahoma's offense in the 2nd half of their game. Army, with a roster of 1 star and an occasional 2 star football players, shut out the Sooners and held them under 150 yds in their last 4 possessions in regulation time. How does Army do this and we can't get just one stop? Frustrating
None of that really tells the whole story, IMO. Army may have shutout Oklahoma in the second half, but look at the drive charts and it isn't because Army dominated the OU offense.
After an Oklahoma INT (Bama dropped I believe 2 in the second half), Army went on a 19 play, 85 yard drive that took 10:47 off the clock. OU moved it right back down the field, only to get stuffed at the goal line on 4th and goal. Then Army goes a 17 play, 65 yard drive in 10:05. Oklahoma gets the ball back, moves back down the field easily, sets up a game winning FG as time expires and misses a 33 yard FG. Army had the ball for almost 23 minutes in the second half, and limited OU to three total possessions.
Bama also got multiple stops in which in a normal game would result in a punt, but Oklahoma knew they had no choice but to try to score on every possession. I think they converted a 4th and 5 from their own 25 early in the 4th quarter. Also as has been pointed out, Bama made some mental mistakes and extended drives with dumb penalties.
I also think the flow of the game contributed to the defensive game plan in the second half. Murray is basically a faster Johnny Manziel, and can put up a TD on almost any play. Once Bama got up big, the only way OU could get back in the game was to score quickly multiple times. It looked to me like the gameplan was to try to limit the big plays, and OU had to take a lot of time off the clock (by their standards) with their second half drives.
It's worth noting that Murray had his lowest completion %, yards per attempt, and passer rating of the season.