QUOTE (undersquare @ Feb 17 2010, 11:45)

Yup there are reasons. But at the bottom of it is that the top teams made other choices. Williams were on the way down by the time they wanted Jenson back. Ross Brawn didn't vote him in his top 6 in the Autosport poll at the end of 08, and didn't get him signed up early in 09. Mac have signed him for a fraction of what they're paying Lewis. Don't expect too much, he's top 8 not top 4.
I think you're on dodgy ground there.
Yes, Button isnt being paid as much as Hamilton, but there has been a complete financial meltdown which affected everything - including Formula 1. Hamilton is probably the greatest asset in Formula 1 at the moment from a marketing view aswell as driving and a WDC to boot, and barely into his mid-twenties. McLaren are going to do everything in their financial power to retain him - and they have. For now.
However, McLaren gave Button a three year deal, which in itself lends me to think that they value him. Button could have stayed at BGP (Mercedes) but he chose to leave and he was reportedly offered more money. I don't think financial terms are the be all and end all so I think it's fairly baseless to argue that point.
I've argued until I'm blue in the face about this ridiculous top 3, top 5, top 8, tiered rubbish. At the end of the day, half of the grid are amongst the finest four-wheel drivers on the planet. If you're going to give them a title contending car, they're going to get very close to it. Jenson got his last year, and did it at his first attempt.
Regardless of whether it was the DDD, lack of Ferrari/McLaren being competitive, RBR blowing, Barrichello's brakes or whatever the countless excuses have been, Jenson still had to deliver, and he did.
However, we're now going to see finally many of these drivers finally paired with each other, and opinion's will soon count for nothing, as we're going to see these boys go at it on the track.