Musk announced this morning that Tesla will make its patents available to the public. That means anyone or any company can use Tesla's technology to make and improve non-Tesla electric car models.
It's not something you see every day, given the current copyright battle between Samsung and Apple.
Think about it. There's only a few hundred electric car charging stations around the country - give or take a few. If more companies jump on board to create more electric cars, there will be more charging stations, and the adoption rate of electric cars will happen much quicker than if Tesla was in on the venture alone.