But using your same line of thought, couldn't one argue that that was last season, i.e. in a virtually different team with different players, and hence there are no guarantees that Barton would be as good this season and beyond?
Aye, he'd done nowt for 3 years, there's no guarantee whatsoever that he could keep up last season's form, and in particular on the sort of contract he seemingly wanted.
What's the sort of "contract he seemingly wanted" got to do with whether or not he would achieve last season's form this season? He started off fairly well, and I would say that more often than not players in the final year of their contract step it up a notch to secure their future rather than lowering their level.