"The better player is the one who's in the same general rating group or above of the other player, who in a one on one match of a decent number of games wins more games than he loses."
This can lead to problems. So Kasparov beats Anand in a match (these all actually happened; these are not just hypothetical). Kasparov is better than Anand. Kramnik beats Kasparov. Kramnik is better than Kasparov (and thus also Anand). Anand beats Kramnik. So Anand is better than Kramnik and thus also Kasparov. Somehow Anand is both better and worse than both Kramnik and Kasparov.
"If Carlsen had lost his match to Anand convincingly or even by a bit, I would say Anand was simply better than him, Carlsen just happened to be more consistent, do better against weaker players, was in better health, players blundered more against him, or a host of other possible variables to get his rating advantage."
What I find especially interesting here is that you would be so happy to make so many excuses for a consistently better rating, yet... I could apply this same logic if it turned out Anand did win. I could just say that Carlsen was having a particularly bad week, or that he "just happened" to fall into Anand's preparation.
The difference of course is that when I am pointing to ratings I am pointing to years of results in many different top level tournaments, (creating a large sample size and limiting bias) whereas the WCC is a one time event, against just one player.
"Hence it's easy for you to say it was obvious months/years in advance of the match, when in reality it wasn't obvious at all."
No, the match happened just as I predicted it; actually, Carlsen won by even more than I had thought, with +3 (I predicted +2 -- I was definitely trying to keep an open mind about the differences between match play and tournament play, but they did not really show in the match. The positions Magnus won were either worse or dead even). Of course ultra sceptics just want to insist that such a prediction was merely coincidental, and that it couldn't have been predicted by the ratings. An interesting fact: The performance ratings of Anand and Carlsen in that match were almost identical to their ratings at that time.