reginos:
Recently, his biggest asset in racing has been the conservation of his tyres, so obviously he could take up a career as a taxi driver if he falls on difficult times any time in the future.
I´d say that doesn´t do his performance any justice. Indeed this year´s rules might favour him and Hamilton might still have that little edge over him in raw speed but his driving, passing manouvres and race intelligence is definitely on par with the other champions out there. Even if excluding the fact that he scored more points than Hamilton, the difference between them is far smaller than in the other competitive teams such as RedBull or Ferrari.
It is interesting to see how well he performs in a proper car such as the McLaren, similiar to his performance in the BrawnGP or the Honda a few years ago everytime the car was competitive. If he would´ve ended his career parallel to Honda´s withdrawal, nobody would´ve considered him to be such a great loss for F1. Now consider what a worldchampionship title, increased confidence and a competitive car can change.
Take a look at Senna in the HRT last year and compare it to his performance in the two most recent races. Take a look at Hülkenberg, who was a very promising driver up to F1 but couldn´t beat Barrichello in his maiden season. Take a look at Fisichella who put the Force India on pole position yet performed poorly in the Ferrari subsequently.
Button´s manners and attitude on track as well as on camera certainly help him and complement Hamilton´s approach so I would be very surprised if they would not offer him a seat for 2012.