Sometimes great teams don't produce in March. Iowa State and St John's both thought this was their year. Iowa State struggled with injuries and flailed down the stretch and lost a very promising season. St John's seemed to be rolling and got shocked in possibly the biggest upset of the tournament.
BYU and the Brandon Davies situation is a great example closer to home. Or the 2020 team and COVID.
To succeed in basketball you've got have a great team and a fair bit of luck.