And in the end, it didn't matter. To continue in the analogy, if the 30th ranked NFL team (let alone the 4th) met the 1st in the Super Bowl, would they also lose 65-7?
As to the original point where this started, you have to go back to 2017 to find a national champion that even lost a regular season game (Bama losing to Auburn who finished season ranked 10/12). For the kind of losses you are talking about (outside the top 20), if you go back to Paul Johnson's first season the national champion had such a loss 2 times (out of 15), in both cases that teams only loss of the year.
The average margin of victory in the playoff final has been 15 points, Not including this year, and in general it's been trending higher over time. Sure, there's still some parody but it has been drying up.