Frankly though everything's all cylicial.
In the next 5 years when Tressel steps down, OSU will go through a down period and have to rebuild under new leadership.
If/when the RichRod experiment ends, Michigan will find a new coach and likely rise back up to the top in the conference (And there's also if RichRod has success too).
Penn State is a squad that competes for Big Ten titles when they have experience on the lines... so every 2 years pretty much they are going to be in the thick of the race (And they still are competing well without experience).
Meanwhile, beyond that you've got the next tier of teams in the B10. Wisconsin has been a team that almost since Alvarez was hired that has been very consistent. They'll be an 8-9 win program consisently and have a year or two where they rise up and win 10-11 games and compete for the conference title. The same could be said for Iowa, and Ferentz is one of the best line coaches in the country. Beyond that, there's usually another team (Illinois, Minny, Michigan State, etc.) that settles in and becomes a thorn in the rest of the B10's side.
If they do indeed come to the B10 I see Pitt developing right into the the second tier.. able to compete solidly when they don't have the experience, and then competing for the conference title when they have the right team.