We will contend for the west again next year.
Mich St will regress with the loss of Walker and their defense wasn't great this year. PSU loses Dotson and Clifford plus many upper classmen on defense. Rutgers is rutgers. I think we'll be fine there.
In the West, NW still has no QB. Nebby unloads a bunch of their defensive stars plus their TE and I expect Martinez may look elsewhere for his final season if he wants to play. Illinois also has no QB but will likely be tougher next year. I'd imagine Bell is gone for Purdue, but they should be solid. IA and WI also have no QB and WI will unload some very solid defenders again.
In short, there's no reason at all this team cannot contend. All teams lose guys each year and I think the perception of how much we have to "replace" is a little bit overexaggerated. I fully expect next Thanksgiving weekend we're playing with the title on the line in Madison (just a matter of who it's against; WI gets OSU, Mich St, and MD, IA gets OSU, Mich, and Rutgers, Purdue gets PSU, MD, and Indy, Nebby gets MI, Rutgers, and Indy)