Jumping the shark is an idiom used to denote the point in a television program's history where the plot spins off into absurd storylines or unlikely characterizations. These changes were often the result of efforts to revive interest in a show whose audience had begun to decline.
While I do find some of the FSFLA's publicity material surrounding Linux-libre to be of dubious quality and appropriateness, I am less than convinced that "jumping the shark" is applicable here.