No, not that big of an issue. Okie Lite is still in a P5 conference, and with two of the schools preventing the conference from expanding gone, the Big XII will actually be able to get up to 12 schools again (should they want to).
Texass is a pipe dream, as the B1G's main network is FOX, and ESPN owns the rights to Longwhorn Network. Texass has to keep tethered to that deal or they miss out on guaranteed money going forward from ESPN (as long as Texass isn't the school ending the deal). Texass would rather be a big fish in a little pond (read: a Big XII without Oklahoma, Kansas), than be a big fish in a large see of bigger fish (Ohio State, Michigan, Penn State, Nebraska). It's why they won't go to the SEC, and why the Pac-12 appealed to them before--there's a set power structure in the former (that they won't break into), and there's a power vacuum in the latter (which is still there, to be honest).
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Kansas and Oklahoma are more realistic B1G targets, but the fly in the ointment right now is Amazon.com. Yeah, that Amazon--they're in talks to buy up the Fox Sports local channels (e.g. Fox Sports Midwest, Fox Sports Oklahoma). These channels are residual from the Fox/Disney merger that are being sold off, and Amazon is in talks to buy them up for their Prime service. Oklahoma has their third tier rights tethered to their local Fox Sports channel, and if Amazon buys the channel and cuts Oklahoma a good deal, they may be inclined to sit tight.
If Amazon falls through or no one else steps up to buy the Fox Sports Channels (which is both possible and plausible at this point), then Oklahoma will be free to partner with anyone they choose for their third tier rights...like the Big Ten Network, which did have a dialog with Oklahoma to put their third tier sports on BTN. Yeah, BTN...not a typo. A move like this would obviously tip Oklahoma's hand toward where they're going when the GOR is up.
And yes, the GOR is up in 2022/2023, but the groundwork for a smooth transition will happen around 2020/2021, when the B1G media deal is up and negotiations will take place for a new deal.