Finally got a chance to watch to the end last night. I was a bit surprised at how triumphant the ending was for it to be Failure, but I can't imagine any different storyform working (e.g. Success with a Goal of Doing). I mean, I can see Lightning having a Concern of Progress maybe, but none of the Elements under that or any of the other Concerns seem to come even close.
I think what's going on is probably the opposite of a Triumph with high Cost -- we have a Personal Triumph with high Dividends, where it was made very clear that the Goal wasn't appropriate. (Dividends include Radiator Springs' future, Sally & Lightning's future, Mater and Lightning's future as best friends, etc.)