I guess you have already forgotten about FSU, Miami and Notre Dame's multiple MNCs and Oregon's multiple 2nd place finishes. Washington has an MNC and has been up there a lot as well.
I posted this before, but there are a relative handful of schools who have dominated the rankings, most of whom dominated in the 60s/70s as well as more recently. 13 schools since 1968 have 10 or more top 5 finishes and each has 6 or more top 3 and all but Michigan (only 1) have multiple AP MNCs. Anyone posting on this board could figure out who those 13 are. There are 7 other schools (LSU, Tennessee, Auburn, Clemson, Washington, Oregon, Colorado) with 5-7 top 5 and all but Tennessee (2) also have at least 3 top 3 finishes. All but Washington (a coaches' title) and Oregon (lots of 2nd places) have an AP MNC. Outside the group only TCU, UCLA, Arizona St. and Pitt even have 3 top 5 finishes. Only TCU (3) and Pitt (2) have more than 1 top 3 finish. So there are only 19 schools (20 if you think CU comes back from the dead) who are consistent threats.