Clemson is the only team outside of current P2 teams to have won the NC in the playoff era, and they were also given the benefit of the doubt in the starting ranks. If you go back to the BCS era, you can also add Florida State and Miami.
Just keep going back and back until pre-1960s, and pretty much all you'll see is current blue bloods and P2, plus, what? Two outliers? Colorado 1990 and BYU 1984? That's it, right?
Look at the recruiting rankings. All blue bloods. Look at the number of NFL players per school. The same dang names.
And now look at how things have shaped up this year so far. Maybe ASU will get an upset, but the teams that were considered to have lucked into the playoffs have been destroyed so far. With the exception of Notre Dame, the non-P2 teams facing P2 teams have all lost by 2+ touchdowns, and the games weren't close.
If anything, the dominant narrative has been confirmed by results on the field.