Why? Who are they going to play that compares to who those other two play? UNC without Wilson? Winning the Big 12 or 10 means beating much better teams than Duke will face.
Because Duke is ahead of Arizona in
both predictive metrics and resume/WAB AND has the inertia and the elite win tiebreaker as it stands. The margin in KenPom is a decent one. It is very hard to catch a team in the predictive metrics at this point in the season without them losing, because each game is just 1 of x and x gets bigger so each game's proportion of the whole is smaller. Arizona and Michigan can't beat themselves or each other, so they have to beat lesser teams in their league.
Arizona does get Iowa State and potentially Houston, which is best case scenario for them. That's 1.6 WAB they can add. Duke will potentially get Clemson and Virginia, which would be 1.3 WAB. Duke is ahead of Arizona by 0.4 WAB at the moment, so Arizona would gain substantial ground, and would put them close to even in the resume metrics.
But then you're still competing with the fact that Duke was already ahead in the minds of everyone and has a likely predictive metric edge.
Michigan is ahead in the resumes, could pull a bit farther ahead, and is basically even with the predictives. They would have the better shot, but Duke has that head to head win.
It just doesn't feel likely, especially because the committee does a lot of the work on the early seeds pretty early in the process, and it typically takes a loss or something major to really convince them to re-jig the board.