It's probably safe to say that BOTH the offense and defense have greatly failed us against OU over the last 3 years.
I do believe, though, that it starts with the offense. The offense has been so awful that there is absolutely no pressure whatsoever on the OU offense when they have the ball. They can just do whatever they want on every drive. You have to make them feel pressure on offense and hopefully get them to be just a little more one dimensional while also putting in their minds the pressure of knowing they must score just about every time to make up for their horrendous defense.
i agree to a point as i agree that the offense hasn't helped the defense out very much against ou, but since the 2nd quarter of the 2016 game they have absolutely ripped up the tcu defense.
big part has been that tcu has not been close to making ou a one dimensional offense. ou has effectively run the football and when you combine that with a pass attack that has focused on isolating the tcu linebackers and safeties in coverage it has been ugly and you can't lay that at the feet of the offense.
in each of the last 4 games there were strings where ou's offense looked like sherman rolling through georgia.
consider:
2016 the frogs are up 21-7 and in the first 4 ou offensive series the frogs have had some success. ou ran 17 plays for 37 yards, punted twice, fumbled once, and the one td was set up on a short field by a hill interception.
then the bottom falls out in the next 7 ou offensive series. they run 41 plays for 394 yards, and score 42 points. the offense didn't help, but are they to play with ou getting the run game working and then effectively isolating westbrook twice on big pass plays.
2017 first game the tcu defense got destroyed in a way that i can't recall a patterson getting hammered in a half. 7 series, 37 plays for 415 yards, and 38 points. riley attacked patterson in a way that was very similar to what we saw starting in the 2nd quarter of 2016. a strong run game and isolating the inside defenders in pass plays.
2017 second game the defense did a better job slowing the offense, the offense does respond, frogs score on 3 of 5 offensive series, gained over 230 yards in the first half and frogs are down by 7 at half.
second half starts and tcu offense can't move and ou has a 1 play and 2 play drive driven by long pass plays again with ou isolates defenders.
2018 the frogs have no viable passing threat with robinson leaving ou to focus on the run. ou rolls their first 4 series and tcu wasn't coming back even with the change at quarterback.
the tcu offense must get better, but so must the tcu defense.
riley's offense has posed a bigger challenge than any group that i can remember since gary has been at tcu. frogs haven't been able to handle the run and the pass game doesn't worry as much about moving the chains as attacking down the field if the opportunity presents itself.