In conjunction with transfer eligibility changes which eliminated the need to sit out a season:
"The problem for would-be bracket busters is that the players that used to lead smaller programs on dream runs through March Madness now defect to college basketball’s big dogs. Shortly after the NCAA created the transfer portal, making it easier for outgoing players to find new homes, it eliminated restrictions that required men’s and women’s basketball players to sit out for a season after switching schools. So those players that went under-recruited out of high school now have a second chance to hit the big time."
Makes sense to me. Don't see it changing; can't blame the players for acting in their own best interests. The only seed higher than #6 left is Arkansas, and John Calipari would be hard to fit for a glass slipper.