Looking at the top-15 highest paid coaches:
#1, #5, #6, #7, #8, #9, #14 have not made a S16 in the last four seasons (back to and including the COVID year, which was the first year I'd have considered Illinois "back").
Izzo (#3), Cronin (tied for #9), Musselman (also tied for #9), and Dana Altman (#12) have made more than one.
I do think our fans (especially those who lived through the two truly great 5-7 year stretches in our program's modern history in the 80s and early 2000s) tend to overestimate how easy it is to make the second weekend, and underestimate how much luck is involved in that even for the very top echelon of college coaches. Totally ignoring the huge changes happening throughout the sport right now.