You sort of miss the point and it is one that I have been stating for some time now, it is irrelevant if you think CU is not your rival, for me Nebraska is mine, it is irrelevant that OU does not consider Nebraska their rival, 56% of your fans believe they are. A rivalry can whatever team you want it to be.
No. That is not a rivalry.
When Nebraska played Oklahoma in the Big 8 every year, that was a rivalry. You take that poll 15 years ago and Nebraska and Texas would have about the same votes, with NU maybe having more (our game was for the conference championship, after all).
A rivalry MUST be two-sided. If it is simply one team, or one fan base, focusing on another team or another fan base, it's not a rivalry.
Look at those results. Most of Nebraska's respondents chose Oklahoma, while most of Oklahoma's chose Texas. Most of Texas' chose Oklahoma. Oklahoma's main rival is Texas. Nebraska's main rival is... nobody. It used to be Oklahoma, but since the advent of the Big XII, it's not. When Oklahoma came to Lincoln I had the chance to talk to a lot of Sooners fans. Young and old agreed - they miss playing us every year. It was a game with magic, against contemporaries, against a team you really feared could beat you even if you played your best.
Colorado, Missouri, Kansas State, Iowa State and Kansas have nothing Nebraska wants. They don't have more prestige, they don't have more wins, they don't have more Mythical National Championships, they don't have more conference championships, they don't have more Heisman winners, they don't have more winners of any other award, they don't have more revenue, they don't have more exposure, their place on the national stage is not more prominent, their stadiums are not fuller, their fans are not more highly regarded. The list goes on. All five of our North brethren are fine teams, with fine fans (mostly) and with fine histories. There is nothing wrong with them, and aside from the fact that we all suck royally, there's nothing wrong with being in a division with these schools.
But until any one of them rises up from the general malaise of all other football teams, makes an effort to separate themselves from the crowd, they cannot be a true rival for the Huskers. Sure, you guys have been beating our butts regularly for the last decade-ish. But losses don't make contemporaries. The body of work doesn't support that.
I'm not trying to be an a$$. I'm just trying to help you get where we're coming from. It is what it is.