It's simple. Pre-BCS, the MNC was entirely a beauty contest. It was almost impossible to "settle it on the field", so voters decided who the "best" team was, and that was your champion.
BCS was a little better, but still a beauty contest. Voters and computers decided who the best team(s) were, and settled it on the field.
CFP is a little better, but still a beauty contest. The committee decides who the best team(s) are, and settle it on the field.
But in no way can you say the path to the championship is objective or earned. Teams can't figure out preseason what to do to maximize their odds. Is it limiting losses? Is it good OOC scheduling? Is it having a CCG or not having a CCG?
The simple fact is that there is no one path to the championship. The path is highly different for an Alabama vs a Purdue. An 11-1 Alabama that doesn't even go to its CCG will have a good shot at getting in. An 11-1 Purdue who narrowly misses their CCG will not. Ever. An 11-2 Alabama that wins it's CCG might get into the championship. An 11-2 Purdue will not. Ever. Because Alabama is one of the "best" teams despite two losses, and Purdue is not. One passes the "eye test". The other does not. It's all subjective.
If you want a "true" champion, you have to give teams a path to the championship. Win your conference, you're in.
Yes, that might result in a year that a team that is not the "best" team actually winning the whole damn thing. But you'll never be able to say that they didn't earn the title of champion.
If you want to crown the "best" team the champion, go back to the pre-BCS system. If you want a true champion, settle it ON the field.