I read that when Fiat bought a part of the Chrysler they killed the program to focus on their hybrid minivan.
Who Killed the Electric Car was a good documentary that explains GM's, Ford's and Toyota's electric vehicle follies. And it's not all blamed on the fuel companies.
The Volt is designed to run like a diesel-electric locomotive, so it's not new tech. Just took them forever to put it in a car. The best benefits would be from short trips, less than 40 miles a day, and plugging it in at night. Could almost use no gas at all. Most people, not all, travel less than that to work and back everyday so it would be beneficial to them. Especially since, unlike the prius, they are not limited to a particular speed and can plug-in.
Drove my wife's Prius on a nature trail around a lake in MO with the windows down and AC off; all we could hear were the birds singing and the small amount of sound made by the tires. Would have been awesome to have a Jeep that could do that.