I don't think Tesla would have been possible if Toyota hadn't blasted the way for them. Before Toyota's work people didn't think any kind of EV was practical.
The classic business book on disruptive innovation, produced before the Prius existed, shows that people who cared actually knew better.
EVs were not viable until battery technology improved enough. Batteries have been improving about 7%/year. Based on those figures from the 1990s and an estimate of minimum acceleration, range, and recharge time to be acceptable on the road, EVs were predicted to become viable for the mass market around 2020.
Guess what. Those trends held and EVs became viable for the mass market around 2020. :-)
