All of that sounds good in theory.
But what actually happens is as follows.
The SEC (and Big 10) start with a dominant number of Top 25 teams. And then when one of their Top 25 teams loses to another Top 25 team, it is a "quality loss", so they don't drop down very far. Even when Pedo State and Oregon struggle early against TERRIBLE non-Big-10 teams, they are STILL hanging around the Top 25.
So if a core of 15 teams just keep sucking each other's *****...the next thing you know, you'll have a BUNCH of 3-loss SEC and Big 10 teams that populate the Final 12. Sure, you'll have an ACC team and a Big 12 team and a non-P4 team...
And then the rest will come from the SEC and Big 10. Remember, they don't all play each other anymore. And only the top 2 teams in each conference have to play in a championship game.
In other words, the rankings become a self-fulfilling prophesy. If you start high, you stay high, even after a couple of losses.
Which is why the complacent "if we keep winning, everything will work itself out, man" crowd is wrong. ACC teams have to lobby to be ranked as high as possible every week, because even one loss will validate the "ACC competition sucks" crowd.