Schools that have been to the Final Four at least once each of the last 5 decades (70s, 80s, 90s, 00s, and 10s):
UCLA
Kansas
Duke
Syracuse
that's it. That's the list. Although, to be fair, this decade is still young and North Carolina and Indiana could still join the exclusive group . . . Michigan, too, if you count their vacated 92 and 93 trips. Edit: brain fart - UCLA is also 0 for the 10s
Louisville went 0 for the 90s, Kentucky went 0 for the 2000s