I would like to amplify these two comments, having been around this rivalry for around 50 years as well. UW has no natural football rivals. They do have "big " games. Big in the sense they are against a well known rival (Michigan, MSU, OSU etc) and the game is at home. Those opponents do not look at UW football the same way though, rather just as another tough conference opponent. The same circumstance holds true for UW basketball. So the emphasis in their school is on these "big" games.
I actually think this is part of the problem from the UW perspective. As much as they’d like, they’ll never be the true rivals of any of the traditional powers in the Big Ten, since those schools all have other closer/more natural rivals. In that sense, they have a bit of the ‘little brother’ mentality vis-à-vis OSU/Mich/MSU/IU in that no matter how good they are, they’ll never be treated as the true rival of any of the programs. But they want to be. Right or wrong, that’s who they view as their peer institutions. Minnesota, Illinois, and Iowa would all be more likely to be natural rivals, but none have had enough sustained success for UW to look up to or consider them on equal footing, so I think they currently downplay those rivalries. Same with us.
If the script flips and MU takes over the top perch in Wisconsin in terms of recent national success in basketball, I think it’d be a different question.