Can we just stop with statements like this. Every game doesn't matter in the current system.
Well, sort of right. How about this, fairly minor, modification: if you want a national championship, every game counts.
Yes, undefeated champions are actually fairly rare, but... remember that game they lost? If they had won it, they wouldn't have had to rely on someone else losing. It counted.
Not a single team that was in the title hunt last year played a single game that was a "throw away." They didn't "rest their starters," unless their starters had already forced the other team's starters to beg for mercy.
Look at the top 4-6 BCS teams from last year - would any of their games turning out differently NOT have really changed the standings at the end of the season? If Bama loses another game, any game - they're out. If we had beaten Stanford or Oregon, either of them would have instantly been eliminated from the picture. There is not a single game on any of those teams' schedules that a different outcome wouldn't have entirely altered the end of season picture. So yeah, every game counts.
Now, lower down the ladder, the bowl system is really very good at making the games count for teams. It is really late in the season until many teams are eliminated from bowl eligibility. And if you are eligible, you still want to win to get to a bigger, better bowl. There's only a handful of teams "playing for nothing but pride" late in November.
That's really remarkable given how many teams play D1 ball...
The current number of teams and a 16 team playoff? Sure the playoffs would be absurdly exciting, but it would mean that about 60 teams would be playing for absolutely nothing but "pride" for the whole month of November. How many of them have coaching staffs that are good enough to keep their teams competing in every game after they've been eliminated? Think hard about the answer to that question...
So, we'll go to 64 teams overall. Ok, instead of 60 team eliminated by Nov 1, you have about 30. Same problem, different scale.
No more than 4 - and rankings are part of the picture...