Together. Sure their contract may be pricy, by the payout is based on profitability for ESPN. They are not looking at a loss leader if they have product to show.
Keeping the conference together is a cheaper option than losing product, or having poor product replacement.
ESPN already had a long term deal with SEC, with or without UT/OU
So keeping the Big XII alive makes more sense. So would it be a stealth move to get the rumor mill started in order to galvanize the existing 8 and forcing them to expand with ESPN making contractual "concessions"