I usually do not follow conspiracy theories, but GM intentionally killed the project so that its success could not be used by congress to try and enforce the restrictions put on car makers in the 90s. They were supposed to be required to produce a certain percent of their cars with electric powertrains, but they didnt want to and so intentionally sacrificed the EV-1 by repossesing all of the EV-1 after the leases expired.
There is a movie about this called "who killed the electric car", and it has remarkable evidence. They discovered car carrying trailers full of EV-1s and offered to buy them, but were turned down. When asked why the cars were there, they were given the answer that nobody wanted them, which had obviously already been disproved.
They followed the EV-1s to a GM testground in the desert, and couldnt follow them inside, so they flew over with a plane and discovered a yard full of crushed EV-1s and some waiting to crushed.
They intentionally killed them because they felt they would reduce profitability.