GM management hated [the EV1] so much that they likely shredded all the engineering designs.
The EV1 was a wonderful car in its day. Today it would be the worst EV on the road. Two seats, poor acceleration, and short range with its NiCad batteries.
I test-drove a Volt once. I drove my Tesla Roadster to the Chevy dealership, told the salesman that I was not in the market for a new car, but was curious to see what the Volt was like. He was very pleased and let me drive it. It had nice handling and decent acceleration. I thought the two-clutch system was overly complicated, but for someone who normally drives less than 30 miles a day but wants to be able to take long road trips (Tesla's supercharger network was far more sparse back them) I could understand its appeal.
Then I took the salesman for a ride in the Roadster and showed him what an EV could really be. (And now the higher trim lines of all Tesla models can accelerate quicker than my Roadster!)
There's really only two serious EV makers. Tesla if you want the best; the Leaf if you want the most affordable. And since those two categories don't really compete with each other, Tesla has no serious competition. Unless you have irrational loyalty to one of the legacy car makers, you'll buy a Tesla or a Leaf, depending on your budget.