Any thoughts as to why that is? Probably a variety of factors in no particular order:
1) Tradition (always helps if you have history)
2) No other major sports in the state to cheer for
3) State pride (is there something that makes Nebraskan's more proud of their state compared to other states?)
4) Football is king. This is probably a chicken or an egg argument. Is football king in Nebraska because of the success of the Huskers, or is are the huskers partially successful because football is king?
It's hard to say. The easy answer is that everybody loves a winner, but we weren't winners in 1962 when our sellout streak started. I'm sure the success of Devaney and Osborne over three decades greatly aided the current situation, though.
I think football appeals on a broad level to the folks who built this state. When Lewis and Clark came through here they called this area "The Great American Desert." It's a tough place to live – too hot in the summer, too cold in the winter, barely any decent spring or fall, the soil is clay and difficult to make produce, there were (at the time) very few trees, and in general life was hard. My grandparents were poor as dirt, and I'm betting most everyone here has similar stories from their grandparents. That toughness is ingrained in the older generations from which us latter-day folks take our cues, and football is a good reflection of that culture. Probably if we were a colder-climate state we'd have embraced hockey more than we do (but hockey is rapidly gaining ground here, too).
There's also the lack of population, which means no other competing sports.
Contrast Nebraska with Missouri and Missouri has a better climate, more scenery, a much larger population, way more things to do, which probably leads to more distractions and less focus on your flagship school.