Don't you think his terrible relationship with Moyes is a more realistic explanation? It's not like anyone else is going to pay him much more than he's already on.
I mean that if a player can't offer the club what they want then they'll get rid of him without a second thought, yet somehow when the roles are reversed that is not OK.
As much as I'd like to see Rooney at Barcelona, unless they're looking for a real number 9, which I don't think they are, it wouldn't be the right move for anyone involved.