Underachievement is a during the season thing. The NCAAs are a whole other beast.
Relative to the talent, I don't think there's comprehensively a more underachieving team in modern program history than the one that had a rotation of six future NBA guys plus two great college players not winning even a share of the Big 12 regular season title nor managing to advance past the first game of the NCAA tournament.
That should have been a #1 seed season with a deep run in March, not a #3 and out in game one.
Did the Shayok team underachieve? Sure, yeah. Not as much as the last Hoiberg team did, though. Assuming both came to play on a given night, I would be putting a lot more of my own money on Monté and Georges.