Right, but, to maximize money, you need more of those match ups. That's what the networks want and will pay for. That's the entire reason for realignment in the first place, they've just been doing it in little moves. Where CFB leaves the most money on the table is having like 5 negotiated TV contracts over 60-70 teams and not pairing those teams together more. This is why you're really only paid for a conference slate, because its the only part of the schedule that networks know is reliable year in and year out. OOC games, even the good ones, are still hit and miss based on if an AD schedules them or not. WHen the contract is signed the network may not even know, so it doesn't factor in. If you put all 70 teams under one global media and scheduling contract and say all 12 of those games will be against each other, now you're going to market with 420 (gnarly) defined games that the networks can bank on.
On top of that, if you own the schedule, you can lay out featured match ups all through the season and through time slots at various times of the day, instead of competing with yourself for eyeballs.
And lastly, you can go full out NFL and start windowing. National window games in various slots. Regional windows to maximize across the board on lower channels. If you want to watch outside your window, pay for the all in package. Oh, you just like the excitement, did you know we offer a redzone package now?
Those are things the NFL can do that CFB can't that would likely double the amount of money CFB could make for literally doing nothing else. Its the only no-brainer chess move left on the board.
And you're right, that's why you need the 70 teams. Blue bloods drive more interest at the end of the year, when games mean more, if they have no losses.