all last year. Wisconsin, with no one and dones was in the championship game a couple years ago, having beat a UK team full of one and dones. The UNC team that was in the final game last year had a ton of upperclassmen. in fact, you included UNC as a team that always have one and dones - the reality is that is wrong. haven't had them the last 2-3 years. they are a 1 seed this year and don't have any one and dones. The teams that consistently have multiple one and dones are a handful and you don't see them dominating college basketball.
in fact, while i admit the quality is down - just a little -i would argue there is just as much parity today as there was 30 years ago.