Since 1985, the 5 seed has never won a national title and there have only been 5 times that a 5 seed hasn't been upset in the first round. In 2019, three of the four 5 seeds even lost.. 60% of the time, 5 seeds win the opening round.
4 seeds fair so much better than 5 seeds, even though there have been a few losses in years past.
Actually, 6 seeds are starting to be bad slots. In the past 10 NCAA tournaments, 6 seeds are only 21-19 in the first round...
From what I found regarding all 4 of those seeds, the margin of victory in the games are INCREDIBLY close.
Here's a detailed history of how No. 6 seeds have fared in the NCAA tournament.
www.ncaa.com