And therein lies the problem. In any given year the third-best (or even fourth-best) SEC team is better than most of the other conference champions. How does a “win and you’re in” playoff system do any justice in that case?
Your argument doesn’t hold water. In the 16 team format the 6 at large bids go to the 6 highest ranking teams that that didn’t win their conference. in that format the SEC will get their teams in.