Whereas the growth at the D1 college level has slowed compared to the first half of this decade. IIRC, there were at least 10 new programs between 2010 and 2015 inclusive in Division 1. Since then, there have been four new Division 1 programs -- and that number includes two new programs this year.
The end result is greater parity at the D1 level. That trend is likely to continue as well, given that there are only two new Division 1 programs on tap in the foreseeable future.
Towson was a final 4 team 2 years ago, so they aren't a good reference point regarding a trend. They were ranked #7 in the country.
While I still think "big dog" programs like Denver, Duke, Loyola, Yale,
and Maryland will still be near the top at the end of the season, the gap between them and the "lesser" teams has shrunk. You're correct that ND needs to take care of business against the Michigan and Marquette, which is no guarantee. They have little room for error - if they get thru March with a winning record, I'll be very impressed.