I don't think you're accounting for a large portion of the fan base that doesn't have a step #2.
And certainly there will always be grumbling, but the question is whether it reaches a critical mass to actually affect change. There are many teams that once competed for conference and even national championships, but are currently content with mediocrity.
People adjust expectations to perceived reality. If the perceived reality is you can't be nationally relevant at Nebraska, people will stop demanding it. That shift in perception is happening whether we want to acknowledge it or not.