Oh absolutely.
While I do believe in things like focus and killer instinct, my best theory for a team like Nebraska losing so much is the weakest link theory. You can do a lot of stuff really well, but if you have just one weak offensive linemen, one weak defensive linemen, and a couple weak members of your secondary, they will get exploited in crunch time. If your QB and playcaller do well for most of the game, but tighten up in crunch time, that's another weak link in an otherwise good team. If you don't have a lot of bench strength, that will also come back to bite you.
There's this wild stat that shows Nebraska is #4 in the nation in total yards per play: the combination of offensive yards gained, and defensive yards given. That would appear to be a great metric for total success, and Nebraska ranks one slot ahead of Alabama.
Weakest link? We are almost dead last in special teams and turnovers.
Maybe Nebraska really is close. Maybe a lot of stuff still needs to happen. I just think they've gotten too used to losing, and that creeps into everything.