Consider the "ultimate playoff", one involving 130 teams, single elimination and seeded (magically). Everyone has a shot. Of course, nearly always 1 will beat 130 and 2 beats 129 and so forth until you reach around 30 where you get "upsets" And then a second round and a third etc.
There are extremely low odds that 130 wins the whole thing, but decent odds that a team ranked (magically) 10-30 wins the whole thing, and the odds are decidedly against #1 (who we omnisciently KNOW if the best team).
That would be entertaining, which is what I like to see, but not really very useful in determining a "true" national champion.