A conference gains its identity from the schools who represent it on the national stage: championships, major bowls, etc. I think it is important that the conference "Royalty" remain consistently dominant. It doesn't hurt for a "commoner" to steal the spotlight now and then, as long as the royalty prevail most years.
Perhaps that is why the Big 12 seemed to have so much resentment toward Baylor in the last two campaigns. Maybe Big 12 folks knew that all was not well and that the Bears should not be the Big 12 standard bearer.
I wonder if the PAC 12 would have had more success with their network if USC and/or UCLA were winning the games that Oregon did in recent years. Oregon as royalty was not an easy sell, however Stanford has been a fine examplar lately.
Now consider the ACC. ACC royalty are basketball schools. FSU, the premier FB power is an immigrant with a relatively short pedigree. Does this tell us that it is crucial that UNC, Duke, UVA ascend to football prominence before the conference can join the club? Clemson has been a consistent winning program, but let's face it, you can't dress her up and take her anywhere.