Well, I'm not quite sure what this piece is doing.
The list is:
Cadillac Escalade
Chevy Aveo
Chevy Colorado *
Dodge Nitro
Ford F-250
GMC Canyon *
Jeep Wrangler
Now, where to begin. First off, the two vehicles I've marked with * are actually the same vehicle with different trim.
Next, you start to see vehicles that are nearing or at end of line of production. As far as I know, GM has already written off the Escalade/Suburban/Tahoe platform. And, if Fiat/Chrysler haven't put the Nitro on the chopping block, they should have, by now. The Aveo wasn't actually a GM product at all, but a Daewoo, and is due for a completely new 2011 model, anyhow. I think GM also confirmed they are ending the small truck platform, so Canyon and Colorado are looking over the abyss, as well. So the lesson of all but two is "Don't buy a vehicle made in a plant that is scheduled to close."
That leaves the F-250 and Jeep Wrangler. Neither of which are really average passenger vehicles. The F-250 is really meant for contractors who need a massive pickup truck. The Wrangler is really meant for people who drive offroad.
So I guess Forbes managed to find two obvious facts:
1) cars that are being discontinued will have crappy quality. (really? you don't say...)
2) cars that aren't meant as daily drivers will suck at that role. (again, you don't say...)
Of course, they probably would have been better off just saying that, but hey, it's more fun to tsk, tsk, over the American manufacturers while trying to sound intelligent.