As @OrangeAfroMan pointed out above, this is not correct because historically after your team lost one game they were not completely eliminated. Instead, they just needed help.
I vaguely remember, pre-internet, keeping pre-season magazines because they contained schedules for every team. Then, when my team needed teams above them to lose I would refer back to the pre-season magazines to review the schedules of the teams ahead of the Buckeyes to figure out the possible paths to the NC for my team.
....
Now consider the exact same situation today:
My tOSU fandom doesn't create ANY rooting interest in FSU/ND, UF/FSU, WVU/Miami, or OU/UNL because my team can make the playoff regardless of the outcome of those games.
This is why I disagree with @ELA 's contention that the MAC Championship matters. I get where he is coming from in that it matters whether the Falcons or Eagles get into the playoff but that doesn't have any impact on the ability of any other team to get in. The rest of us would simply know that either the Falcons or Eagles will get a spot but which one has no bearing on our own teams' ability to get in. Those two will decide their ONE spot between themselves and that is it.
With a 12-team playoff basically all of those teams are getting in so the only thing on the table is the order and why do I care whether ND or FSU is #1? Either way it isn't my team.
So, I wanted to give this a slightly more nuanced response. The issue with "every game matters" is that as you said above, it's sort of squishy. It's "not every game matters, but a small subset matter a great deal, but if you're some teams some years, they don't matter, and sometimes they do."
The old system was get undefeated, NC, or lose once, try your luck. And I get there's a certain appeal, but it just means the appeal is watching standings for the most part.
The argument about gloaming onto other national games is … Interesting, I guess. But if OSU had lost to Rice or Michigan State, you as an OSU fan wouldn’t have cared at all. And if you wouldn’t have cared at all, why would the 50-some fanbases with a loss by mid-October care? It’s a self-defeating argument. As a Wisconsin fan, I care about those games because I care about the rat race, but I’ll care about that regardless. (I also care about the MAC title because the national title race has always been a part of my CFB experience, but not front and center like it seems to be for many)
You ask, “why do I care whether ND or FSU is #1? Either way it isn't my team.” Why should I, or most fanbases care if it’s ND or FSU or OSU or Oklahoma if it’s none of our teams? In essence, you’re saying, “We need this system becuase it makes me care, but if most fans took my outlook, they shouldn’t care.” And that’s not a reason to keep something around. The other issue is that this system comes with all the BS. With this system, you will parse out each team’s rode to -0 or -1 each Saturday night. Then you have the rankings, which in this case matter a ton, so you get to talk rankings. And after the rankings come out, you again project and lament and such. And all of it is for scenarios that won’t happen. Now, I know there are some people who enjoy that. I don’t. And most people say they don’t, but for some reason, the desperately want it to be front and center int he CFB experience.
I’ll step into an aside for a moment. I didn’t have teams in the thick of the race late into the season when my fandom was really crystallizing in school (I did ride that wave with Cal and OSU in HS, but that’s a different story). But I did watch my alma mater go 5-0 a bunch. 5-0 is an interesting record. If you have hype it builds it. If you don’t, the hype comes slow, and people say “where’s the respect?” You can get it with two body bags, a down P5 team and a couple Big Ten wins. It’s enough to make you say, “Hey, every game counts, and we have no losses.”
But it tends to end. You learn the truth we all do. The mattering is in the finishing, not the start or middle. In theory, the 28-12 win against Vandy matters because it COULD have been a loss. But it wasn’t. And you’re instead out here lamenting that you lost too many sports in the rankings because the voters didn’t watch and see it was really 28-6 until garbage time. Outside the zone that gets an OSU or UF fan to care, you learn to appreciate your team/or other teams you like and the national race as separate. And as a separate thing, it’s a certain kind of good, but comes with so much BS, and isn’t necessarily any more worthwhile than good teams, playing each other, with stakes on the line that both actually know.
I know that’s too long, the summery comes down to the bolded paragraph. If the best argument is that if you root for five teams in it in November, it’s wonderful, but even fans of powers often are out of it and admit they don’t care, then the argument that it’s truly worth holding onto rings mighty hollow.