I live in Nebraska and follow them as a second team. NEVER have there been that few at a game. Ever. Perhaps near the end of an Ohio State drubbing in 2017, but not during the first half. Even last year when Nebraska was 3-7 and hosting Michigan State in the freezing snow they had a full stadium:
https://www.youtube.com/watch?v=SIK_-rLGE_s
They are an outlier for a reason. The fans are dedicated. It doesn't win games but it doesn't hurt either. GBR.