I'd have to agree with the facts the article uses. Penn State twice got to be NC by beating the likes of Pitt, Rutgers and Maryland year after year. I think if you ask Jo Pa if his schedule is tougher now than it was in his glory years as king of East coast football you'd get a "Hell yes," answer.
You can point to Vandy and Kentucky, but Indiana has one of the worst records in Div 1 and Northwestern isn't much better. And isn't it ironic that IU is the team who has played the most games against SEC teams including a newly created (new in the sense that we're talking about 1920 to present) annual mix up with Kentucky... which they haven't exactly dominated.
But you don't get to be SEC champ by beating Vandy and KY. You have to go through a brutal schedule. in which you have to beat at least half of the teams on their 'A list': Alabama, Tennessee, Georgia, Auburn, Florida and a second tier of LSU, Ol Miss, Mississippi State, South Carolina (and don't you think their coach doesn't wish they were back in the ACC?) I don't see a diet of cup cakes there.
I would suggest is that there is a degree of bias to the Bowl games. The Orange, Sugar, Peach, Citrus, Independence and Gator bowls are essentially home games for the SEC/ACC. Indeed these bowls were created to make tourist bucks and to showcase SEC/ACC football. Yes, each school receives the opportunity to the same number of tickets, but the SEC school gets the locals. I have no way of proving it, but I would suggest that geography dictates that the southern teams have the home field advantage. This difference also means changes in training schedules and facilities are going to be more significant for a Big 10 team. It also comes down to something as simple as uniforms. How many times have you seen OSU in scarlet jerseys at a bowl game?
If home teams are more successful than visitors in the regular season does it not suggest that they would be more successful in the Bowl season also?
I might also add that there weren't many SEC - Big 10 matchups in the 1930s - thru the 70s. During that time the Big 10 only allowed one team to play in a bowl game, and when they were generally conceded to be the dominant football conference. During that time Big 10 schools were integrated and thus "Un invitable" to many of the bowl venues outside of the Rose Bowl. It was after USC came to town in 63 and blasted Alabama, 35 - 7 that Bear Bryant opened the SEC to the black athlete. What a change that has made in SEC football.
But let's give the SEC credit where it is due, theirs is strong league indeed and perhaps the best in current college ranks.