As long as Americans continue to demand that even their Camry's need to be quick off the mark we will continue to have relatively poor gas mileage.
I once got a test drive in the latest performance version of the Camry. Yes, it was fast and performed well, but it will never beat a BMW and what's the point? If you settle for a Camry then you ought to get better gas mileage rather than faster 0-60.
It's not demand as much as situations require it. Our roads are outdated, some by nearly a century, and if you can't accelerate quickly, you're going to get struck.