I just said I wouldn't have called it historically terrible, but that's because you and I were operating on different baselines. I was meaning history compared to NCAA major conference history. Not compared to Big 10 history. But you're right that this is a very bad showing for the Big 10. Have to go back 14 tournaments to find a worse showing.

2021 - 0 Final Four, 1 Sweet 16
2019 - 1 Final Four, 3 Sweet 16
2018 - 1 Final Four, 2 Sweet 16
2017 - 0 Final Four, 3 Sweet 16
2016 - 0 Final Four, 3 Sweet 16
2015 - 2 Final Four, 2 Sweet 16
2014 - 1 Final Four, 3 Sweet 16
2013 - 1 Final Four, 4 Sweet 16
2012 - 1 Final Four, 4 Sweet 16
2011 - 0 Final Four, 2 Sweet 16
2010 - 1 Final Four, 3 Sweet 16
2009 - 1 Final Four, 2 Sweet 16
2008 - 0 Final Four, 2 Sweet 16
2007 - 1 Final Four, 1 Sweet 16
2006 - 0 Final Four, 0 Sweet 16
2005 - 2 Final Four, 3 Sweet 16
2004 - 0 Final Four, 1 Sweet 16
... and before that it's not as easy to look up on Wikipedia. But your guess is pretty accurate - in the 16 years before this, Big 10 had 12 final Four teams (0.75/year) and 38 Sweet 16 teams (2.38/yr)