I've even heard people say it's because of "wind." As in, because it's typically windier on the plains than in any other part of the country. That just sounds ridiculous.
I say the answer to all of this is "no" and I'd present Ohio State - consistently the best team in the conference - as evidence. They run a spread offense, and even though it doesn't go as fast as Chip Kelly or do identical things it's still similar (and yes, I know they have a big emphasis on the power run as well in their scheme).