Interested in declaring a national champion among their ranks. They cannot do so without playing at least the mega conference. And they cannot legitimately do so while ignoring another half the power football teams in the country, regardless of how they look down on them (academics, red states, etc). You’ll have 40ish current P5 teams in these two mega conferences and you’ll have 40ish P5 teams probably 2 other conferences.

Half to the country is not going to simply bow down to These two conferences. Just as the mid major conferences and refused to simply bow down to the BCS/P5 over the last 20 years. If you want your declaration of a national champion to be recognized across the nation then you cannot exclude half the nation.

Now, perhaps the 2 mega conferences set up the new NC tournament. Perhaps. But if they do, there will have to be access for the other conferences for the format to be widely accepted nationally