IMHO this is the death of MSU as part of the "big 4" in the East. I think they're destined for a slide back to join MD/IU/RU. Maybe still remain above those programs, but not ever in legitimate discussion for winning the division.
MSU's most recent resurgence was partly due to Dantonio, but it was also partly due to capitalizing on big brother's malaise. Dantonio was a great coach in the Kirk Ferentz model -- get halfway decent talent, but develop it better than most. They never had UM/PSU/OSU level talent, but player development helped at least keep them in the conversation.
Not that big brother has managed to get a division title, but they've probably reestablished their dominance in-state. MSU's only chance to maintain parity is if their next coach is an absolutely PERFECT hire. Someone with the personality to keep their recruiting on trend if not improve it, who also has the ability to develop players much better than average.