Because Jim Tressel broke the league and came up short in 06 & 07. The latter was just bad luck as that 07 team was not one of Jim's top five squads. 05 & 06 would obliterate them. 02, 03 would take their manhood. 10 would win by 10+, 08 is closet but probably wins and while 04 was worse overall I'd be curious to see the result of a bowl season matchup.
Because the big ten actually had to play Pete Carroll, something that basically didn't happen to the top dogs in the south east (that stayed remarkably insulated until the league dynasty was well in place, with a few exceptions, kudos lsu)
Because Michigan has never recovered from Tressel and if they had remained good and kept beating the sec, the rhetoric might be much different. Or espn would still use the same hypercritical hyperbole against the league that it never ever uses on the acc or b12, allowing them to recruit their way out of rampant failures on the field.
Because Michigan traded in a long line of NFL qbs including a returning one in mallett so they could have forcier, Robinson, Gardner and later Morris. All of which were secondary to a foolish all in pursuit on huge osu lean terrelle Pryor.
Because the last two football powers didn't have much success after joining and certainly nothing close to what they enjoyed in the decades beforehand.
Because the Midwest cannot support osu, up, nd, msu and have enough left for the weak members of the b1g.
Because the league recruits poorly as a whole, especially compared to the resources and "resources" at lower rung schools in the acc, sec and b12. Cheating happens everywhere but it is more systemic in the south, especially comparing Wisconsin or sparty to ole miss or Clemson, let alone Purdue vs miss st. The commitment to winning, especially with such apathy about the other sports, creates a very different pursuit. Far better coaches, recruiters, facilities and methods.
Because espn isn't directly influencing and protecting the title berths and recruiting prowess of second and third tier b1g schools that do not accomplish anything on their own but membership.
Because when the big ten loses to an unranked foe in conference play they free fall. When the sec does the same, Goliath stumbles mildly in the polls while David shoots up to around the same spot or higher. This happens virtually every time until people just accept this insanity and double standard and hope their conference can get a title berth if the six sec teams ranked in the top 12 lose first.