Some EV enthusiasts in forums say GM would have been much farther if it had not crushed the EV-1. But EV1 wasn’t destroyed as GM needed time and lessons, which went to develop Volt and Bolt. Besides, I don’t think GM would have been too much further. The bottle neck has always been battery technology. If you look at the history of electric car progress you will see that it would have taken a lot more than simply GM acting alone in battery technology. The breakthrough has mostly come from the mobile phone industry.
Also, GM didn’t stop development of electrified cars. Most employees from the the EV1 program moved over to the Fuel Cell program. Which is just an electric car with a different way of storing the energy. When GM started the Chevy Volt program many moved back over from the fuel cell program. The chief engineer of the Volt – Andrew Farah was originally on the EV1 program.