Looking at teams all season and going into the tournament, there have always been 15-20 teams a clear level above everyone else, and though even within that group there were tiers of class, there was just a group of teams that were never going to fall out of the top 20, even with regular losses on the road to unranked teams (which does happen every year, usually even more pronounced).
If you look at KenPom right now, there is a group of 15 teams that is a good 10% better than the rest of Division 1 statistically. Of those, only one has lost, and Auburn had fantastic metrics against a really suspect schedule. Kentucky was never really in that group, they just got hot late and beat Tennessee and somehow their perception went from a disappointing middling seed to a top 10 team overnight without really earning it.
Those 15 teams:
Tier 1: UConn, Houston, Purdue
Tier 2: North Carolina, Tennessee, Arizona
Tier 3: Iowa State, Marquette, Illinois, Duke
Tier 4: Creighton, Baylor, Alabama, Auburn, Gonzaga
After that? It's MSU and WIsconsin with BYU, Kentucky, San Diego State, St. Mary's.
Now, it's wild that 14 of those 15 teams could feasibly make the second weekend (and the 15th could have as well but they Yaled it up), and the 15th S16 team could be from the group just below that (with NC State the obvious outlier at this point), but it should make for some fantastic basketball next weekend when that weekend is usually a mix of Cinderellas that got hot the previous weekend and revert to form and juggernauts that blow through those outmatched Cinderellas on route to the championship.
