Coach K has the same amount of tournament wins as JB the last 5 seasons. He’s vastly underperformed with the talent he’s brought in over that period.
I've said this in other threads. There's more to college basketball than the tournament. Did JB fail as a coach in 1980, 1991, 2004, or 2005? I don't think so those were great years.
Why do you limit things to the last 5 years?
When you are a consistently high seed, you have a greater chance at being upset. If you look at JB's tournament record I bet you'd see our performance relative to our seeding is worse when we are a high seed than when we are a low seed. I really don't think that's surprising. If you're a 1 seed anything less than a final 4 is underperforming, if you're a 2 anything less than an elite 8 is.
Duke has been a 1 or 2 seed under coach K 24 times. They reached the final four in 8 of those years and won 5 NC's. Under JB we have been a 1 or 2 seed 8 times. As a 1 seed we made one elite 8 and two sweet 16's. As a 2 seed we made one elite 8 and lost in the NC game once. So as a 1 or 2 seed Duke has made a FF a third of the time. As a 1 or 2 seed we have made it there an eighth of the time. So it could be argued that given elite talent, Duke maximizes it more often than us.
Now it could be argued that we do better on the average with less than elite talent since we've made the FF four other times when we were lower than a 2 seed, once as a 3 seed (won our NC and I would argue our talent was pretty close to elite), twice as a 4 seed, and once as a 10. Of course Duke as only been lower than a 2 seed ten times with K as coach. They were an 8 seed once, a 6 seed once, and a 5 seed once. The rest were 3 and 4 seeds.
Now, regular season success is what determines whether you even make the tournament and what you're seeded, so it can't be ignored. And recruiting is part of college coaching, so I wouldn't hold it against a coach for winning with elite talent.
So, as I said. If you question whether coach K is a good coach. I question your ability to analyze coaches.