Back in 96 EV technology was super expensive. Nickel Metal Hydride batteries were even heavier and costlier to produce than they are today. Since at the time there wasn't a wide-spread demand for EVs (other than in California) the General decided it was too expensive of a project and scrapped it.

Now that gas is nearing $5/gallon and Hybrid/EV cars are in high demand, I bet they're rethinking the decision.