Il_leone, but the WDC is not about pure speed, it's about who gets the most points. If you want pure speed I'd suggest to watch something like dragracing. I don't argue that Senna was better in pure speed than Porst, but Porst was better in getting more points.
In the Hamilton-Button situation, over 3 seasons, Button was better in getting more points. He was also better in getting championship position (2nd ,5th, 5ht, compared to Hamiltons' 4th, 4th, 5ht). But Hamilton was better at getting wins and poles. But Button better at getting podiums.
It's all about what your defintion of being better is.
If I was to hire a racing driver, I'd rather hire Hamilton than Button (for the same price at least). Hamilton has more potential, but so far he hasn't been really good at proving he really has more potential (in getting points I mean) than Button. And that would mean I would not be willing to pay him more than Button at the moment, although he is definitely the faster driver.
But Hamilton did very well this year. He really improved to last (and earlier years). Then he always made some erors which really cost him. He didn't make any of those this year. He's been let down by reliability and has been taken out twice by another driver with no fault of his own. But in the end, the bottom is that the points count.
I think it's a shame that Hamilton leaves McLaren, but very understandable from his point of view. I think he his little chance with Mercedes to be running for WDC. And I think that McLaren would have a better chance with Hamilton than with Button. Button can become WDC, but he needs a good car more than Hamilton.
Over the past three years, Button did a lot better than I expected when he went to McLaren. I expected Hamilton to beat him easily. That didn't happen, and in fact (imo) they were roughly equal over those years.