To be fair, it was only one McLaren and one Ferrari in 2009 that would out-qualify Button, and the Ferrari didn't always, the Toyota's and BMW's were only strong at some tracks, and it as usually just one driver from that team.
Barrichello's qualifying average at the second half of the season was "4.3" it would have been a bit higher but he couldn't go for a second run in Q2 in Hungary and qualified 13th, for hungary is you put in his average qualifying compared to Button it would have been "3.6". While Button's qualifying average at the second have of the season was "8th" and that was with no problems like Barrichello. That's from Silverstone onwards.
I don't even know why I put those statistics up, I was working through them and forgot my point.
Button only had one DNF in 2009, Vettel will surely have won, the lowest position bar the DNF Button finished in 2009 was 8th, the last points scoring position, Vettel has another advantage here as he can finish 10th and still score a point.
Barrichello had 2 races where he didn't score points in 2009, compared to Button's one, Vettel had 5 non-scoring finishes and that was Button's nearest challenger, Webber had 4.
This year Vettel's had none so far,, as does Webber, Hamilton has 1, Alonso has 1, and Button has 2.
Is Vettel really doing a Button? Well so far I have only assessed Button's second half of 2009, and it looks as if he slipped quite a bit, I don't see that happening with Vettel, as he is a better qualifier, and after his 6 wins he has finished 2nd three times and 4th once, while Button at the same time after his 6 wins finished 6th once, then 5th then 7th twice.
EDIT: Keke beat me to it!