That's recent history. There's also the mid 80's where you had Georgetown, St John's, Syracuse, and Villanova. However, in between these eras, you pretty much had UConn and nobody else, while the ACC was pretty clearly the best conference in NCAA basketball. Duke, UNC, some very good GTech teams, some very good Wake teams, Maryland toward the end of the 90's and early 2000's.
I realize you said "almost always", but even that is overstating it, IMO.