Don't forget the "bragging rights" and recruiting factors as well. A lot of Nebraskans live and work in Iowa and vice versa. That, by itself, creates something of a "rivalry" atmosphere. Nobody wants to have to talk to that Iowan who works in Omaha and you have to see him on Monday after Iowa kicks our ass on Saturday. We also don't want to be losing recruits out of Omaha to Iowa. We need to win the Iowa/Nebraska areas recruiting battles.
Not to mention some of us have close friends that are Iowa fans, like myself.. The Riley era has been pretty tough too deal with.. And it also trickles down to Basketball and Baseball games too.