Why are you surprised?
I know US car makers can build fantastic sports cars, they just have to really want to do it and put their heart to it.

I'm sometimes surprised how dumb US car makers are. They have all those great V8/V10 engines and they don't do anything clever with them. Look at the cheap Corvette/Viper interiors, couldn't they have done better? And why is the Cayenne Turbo the most powerful SUV, why not a SUV from the US, the mother country of all SUVs?
I think US car makers should be more curageous and start building what the customers are asking for.