I doubt it's much worse than any other make of car. Lots of folks only keep cars for a few years. The only long-term cars people keep are run-arounds, cos if your car is for fun it can get boring sticking with the same thing.
I do think people just get bored or can't afford them any more so sell them, I get bored with my car after a while so I get it tuned more or change something on it. I've had mine for 2.5 years now and have no intention to sell it any time soon. (especially with it's new spec).
I have never understood the fascination with people worrying about previous owners, also the fact people that low milers GUARANTEE a mint car. Which in my experience a lot of the time simply is not true. But its something psychological about it.