If you go back to the year 2000, The mid major conferences had much better seedings than today. There were 18 mid major schools with seeding of 12 or better (6 of the schools are now P5, so 12 schools that are still mid major had seedings 12 or better). Five schools were favored based on their seeds and 3 were tossup 9 seeds. This year, there were 10 mid majors with seeds 12 or better, but only 2 were expected to win based on seeding and 2 were the 9 seed in tossup games and 5 mid majors won, so they already have exceeded their win total based on seedings.
Look at the 6/11, 7/10, 8/9 matchups between a P5 and a mid major plus the one playin game between a P5 and a mid major. The mid majors were 5-4 and the point differential in all of the games combined was 6 points. The mid majors belong.
Due to the use of analytics and specifically the NET, P5 schools are advantaged over mid majors and get better seeds. There has to be a better way to seed the mid majors.