It is somewhat dependent on how good the high school classes are. So, when there was no EYBL in 2020 and only an abbreviated season in 2021, that greatly hurt the development of those players. This current crop of freshmen class is putting up dominant numbers. They had the normal reps, unlike some of the prior groups... it also depends if you're getting top-10 players, or perhaps fringe 5-star recruits. Big difference.
Kentucky has missed the past 4 years. Covid year doesn't count. But, guess what? UConn and Villanova have had long spells, too. You mentioned UNC as a team that mixes young talent with veterans. But guess what? They've failed to make a Regional Final in 5 of the last 6 tournaments (and it'll likely be 6 of the last 7 after this year). The number of OADS Kentucky has had has actually gone down in recent years. Past 4 seasons, they had 5 freshmen that went in the first round (Duke had 6). A lot of those classes from the prior decade had 3-4 freshmen go in the first round. They're not getting multiple top-10 guys like they used to get.
At any rate, who wouldn't take those odds of reaching a FF 6 out of 23 times - or a Regional Final 12 out of 23 times?