Maybe too simple an explanation, but it seems like it's worth it to sit out a cycle and let the old guard get a little bit older -- that way you're (Carlsen) is much less likely to fail. Carlsen's generation isn't much of a threat to Carlsen.
I think of it as a mix of fear and logic. He's guaranteeing his future success by running away today. IMO the unhappiness with FIDE policy is a red-herring so to speak, even if Carlsen himself doesn't think of it that way.
Not at all admirable, but it makes sense. And I'll be disappointed not to see an Anand-Carlsen match asap
My 2 cents.
Three good posts in a row, making what I believe to be, sound arguments.
I too think that Carlsen has missed out on a great opportunity to begin building legendary status. He won't get it from me until he has shown his strength in the classical contest, matchplay.
Until then, he's just another "nearly man".