While technically true, they've gone three times, gone 1-and-out twice. Not a ton of accomplishing outside two programs.
Anyway, it's a year where there aren't a ton of high end options. OSU is a little weak on the resume, in part because a mess of good Big Ten teams were less good than normal. But they kicked the hell out of most teams, they're crazy talented and most of the other options are not inspiring.
On your first paragraph:
There certainly isn't much "accomplishing" outside of Bama/Clemson. They have four CFP semi-final wins each. The entire rest of the universe has four total (one each for tOSU, LSU, UGA, and Oregon).
With that said, the gap after Bama/Clemson is large but tOSU is the CLEAR #3. Oklahoma equals tOSU in appearances but they are 0-4 in CFP games while tOSU is 2-2. LSU equals tOSU in CFP Championships but LSU's one Championship is also their ONLY CFP appearance while tOSU has three others and tOSU was close every time they missed.
On your second paragraph:
I think the weakness after Bama/Clemson (whether perceived or actual) is a big factor here. Ohio State's six games would obviously have done them in if the B12 and P12 had produced 12-0 Champions but that was never possible and even if the B12 and P12 had managed to produce undefeated champions who knows. As it is, your next highest ranked teams were:
- A 10-1 non-Champion ND that got curb-stomped in their last game by Clemson.
- An 8-1 non-Champion aTm that got curb-stomped by Bama.
- An 8-2 B12 Champion OU with a loss to a sub .500 team.
- An 8-3 Florida with a loss to a sub .500 team.
It is one thing to say "6-0 isn't enough", it is another to explain which two of those teams should be in ahead of them. None of them presented a very compelling case.