It seems like it's more than know-how. It's almost like Griffin thinks it's his job to get every last half-foot despite the impending impact with a 260lb linebacker bent on his destruction.
the most convincing explanation I've heard (granted filled with anecdotal evidence, arm couch psychology and pure speculation) is that Griffen was drafted to be the savior and he's trying to live up to the role while Wilson and Capernick were always expected to come along slowly and neither has the same degree of pressure, so they're more willing to give up the extra yard or two
