The idea was to sell each game ala carte for a lot of independents. I'm not good at researching it but I believe the 4 million viewer mark has been set as the point where media partners are willing to pay premium prices.
If the market value of all twelve games were broken down on an individual basis, I don't see USC's current schedule busting that 4 mil mark with the possible exception of the USC/Notre Dame game. So they really only play one game the broadcasters desire enough to pay up. (Maybe two with the UCLA game.) But, if their schedule included say UCLA (Cross town rival ya know) #1ACC team (Clem, FSU, Miami), #2 B1G (tOSU, Michigan, Penn State), #1 Big 12 (Okie Lite, Baylor,), #3SEC (LSU, A&M, Florida), Notre Dame, BYU plus five mid range teams from the P5 schoos, one would think that would be more attractive than their current schedule of Rice, Stanford, Fresno State, Oregon State, AZ State, Wazzou, Utah, Arizona, Colorado. Of course those other P5 teams listed would have to be independent or willing to schedule USC. Again, each game would be negotiated individually.
I've just been under the impression the media is willing to pay for some less attractive matchups just to get the attractive ones. Like they really want tOSU/Michigan but are willing to broadcast Illinois/Rutgers just to get the former. No?