The blue bloods in each conference, by themselves, don’t provide enough inventory to justify the contracts they signed. On their own, they wouldn’t come close to receiving what they get from conference distribution.
TX, for example, received almost $35M from the Big 12.
The LHN gives them an average of $15M/year, over the 20 years of the ESPN contract. This year, that amounts to $13.5M.
Without its membership in the Big 12, and its lesser teams, it wouldn’t cross $20M.
If it was more lucrative to be apart from those lesser teams, the blue bloods would have done so long ago.