One thing that jumped out at me is this table. In it, a majority 56% of survey respondents in the U.S. are not willing to pay any premium for an "environmentally friendly car".
And also, consider the odd result for the people who would, if they vehicle would pay for itself. They are willing to pay up to $3,900 premium, but expect it to pay back in 3 years. That implies an expected fuel savings of 325 gal/year at $4/gal. A 27mpg car uses 444 gal/year with a typical 12,000 mile/year driver. This means people expect the equivalent of going from 27mpg to 100mpg, for $3,900! Clearly, this is not going to be realistic in any short term time scale.
The closest vehicle we have now to 100mpg is the Volt, which carries a premium of about $15,000 (compared to a well equipped Cruze).
So, basically, American consumers are saying, "we'd love fuel efficient cars--as long as they don't cost much (or anything) extra".