I would make the case that Nebraska is already out. They have been mediocre for a quarter century now. And on top of that, they don't seem to have any path back to national relevance. They don't have a recruiting advantage, the brand doesn't hold blue blood like value with younger generations, they don't have a money or facilities advantage over their peers.
Last top 10 finish was 2001, 24 years ago.
They only have 7 bowl wins this century.
They recently went 7 consecutive years without a winning season.
Last time they won their division was 2012 in the pitiful B1G West.
Only had a winning conference record once in last 11 years.
Have lost 10 of 11 to ToE, including 7 straight in Lincoln.
There is a lot of ancient history to prop them up on that graph, but I would consider their status already revoked. I think the comparison to an Indiana basketball is a good one.