It is a game of poker right now. The problem Nebraska has is that if Mizzou goes to the Big Ten and Colorado bolts to the Pac 12, then they are either stuck with being the forgotten team in the north of the Big XII - OR - they would be forced to form their own league with Kansas, K-State, Iowa State and probably some Mountain West schools (Air Force, Wyoming, BYU, Colorado State, etc.).
So if your three options are potentially 1) joining the Big Ten and earn much more revenue, 2) being second fiddle in a Texas-heavy Big XII with less revenue, or 3) being a part of a potential new "Great Plains Conference" with the likes of Wyoming and Air Force and who knows about revenue --- then choice is obvious...you join the Big Ten.
Nebby's problem is trying to beat Missouri to the punch. If Mizzou leaves for the Big Ten that triggers a lot of potential problems for Nebraska. If Nebraska beats them to the punch, then at least they're in a big power conference with tons of TV revenue. Nebraska could gamble and say the Big Ten will go for Notre Dame, Pitt or Rutgers and the Big XII stays in tact. But, that's a gamble. No doubt Osbourne is preparing his fans for the possibility of joining the Big Ten just in case.
I've said this before, but Nebraska joining the Big Ten would change the landscape of college football (although meaningless addition in basketball). ABC/ESPN/BTN would be salivating at the possible matchups:
Nebraska-Ohio State
Nebraska-Penn State
Nebraska-Michigan
Nebraska-Minnesota
Nebraska-Iowa
Nebraska-Wisconsin
ALL of those matchups bring a national interest. Nebraska is a namebrand in college football. The Big Ten will have to decide if adding that national namebrand is better than adding TV sets and the millions of $$$ that come with that (Rutgers, Missouri).