TCU was among the top teams in the country in 2014 but didn't have the political clout to make the final four. They had a terrific defense. They killed Ole Miss who had plenty of name DL's including the top player at any position in his recruiting class. Ole Miss gave Alabama their only regular season loss, but lost by 39 to TCU. I think the Frogs were as good as anybody in the playoff. If they hadn't got a little jobbing at the end of the Baylor game in Waco, they'd have had a great chance to win the NC.
I think in the days of no huddle spreads, that it might be more important to have quality DLine depth than one elite guy. There is no doubt that the best two teams in the country this season had terrific big guys on both sides. I'd say that it takes having great players at 21 positions to be able to overcome having a less than great quarterback. Bama had that. Sometimes, it's just having a hot quarterback. Theirs made the plays in the fourth that were huge. If he hadn't, and if Clemson's quarterback, running back and several other players hadn't bee affected by injuries, I don't think Bama would have won the NC.
For years, I've claimed that the RRR team with the best defensive tackles usually wins, and that is still normally true. But you can have outstanding tackle play, without having elite recruits there.
The Sooners certainly did in 2000 with a terrific rotation.