I don't particularly buy that, SP, but let's say you're right and maybe Bitton is an anomaly.
In Bitton's case, clearly he's got the talent to be where he is, otherwise he wouldn't be here. He wouldn't be playing at this level if he didn't have a high degree of drive to match his immense talent.
And I don't think Bitton's a player with "limited ability" who is "just OK to go along for the ride." I think he's much more than that, and he proves that whenever he takes the pitch. Not playing the game with anger or arrogance is not a drawback -- on the contrary, I think it's an asset. And I don't think selfless play for the good of the club is a drawback either.
As far as "something to prove," Bitton has proved he is a player we can depend on to come in and play the positions he's asked to play. So when a player can do all that, regardless of his motivations, I think he's definitely an asset to the club.