It probably is easier to win in the SEC, especially the east. You'd basically be going up against Georgia and probably Florida in a few years.
Just like the big 10, when you avoid the difficult crossover games, it's pretty easy to win 6 or 7 games in conference.
The SEC and Big 10 bias from ESPN and the playoff committee probably isn't helping either. If Big 12 coaches start thinking the only way they can get into the playoff is to schedule difficult non-con, then go undefeated in conference play, while other conferences can lose 2 games, they might want out.