Unable to compete with teams from the SEC who are all bigger, blacker, and faster. They pay their coaches, assistants, and strength coaches LOTS more than what the other conferences pay theirs. A team like Michigan will NEVER win a championship while they continue to draw their recruits from the talentless shitholes of Ohio, Michigan, and Illinois. If you can't get the bulk of your recruits from the Southeast and Texas, you will not be able to compete.
The southeast regions and Texas LOVES their college football whereas places like the northeast and pacific regions gravitate more towards the NFL. Plus, playing against weak opponents in the Big 10 or ACC all the time doesn't prepare you for high level competition against the SEC and a few select non-SEC teams in bowl games.