Nice to see that electric cars are seen as a viable alternative but I think we're a long way away from the "tipping point" which won't change until consumers attitudes change.
I can't see electric cars being at the same or less purchase price than gasoline powered cars for some time. Don't forget there is also the cost of the charger installation and this could be a very significant cost for people who live in (rented and owned) apartments.
Maybe this will change with the $35k Tesla in 2016/2017 but even that is significantly more expensive than a basic Corolla - if the cost difference is $10k and the car is driven 10k miles/year and gets 25 miles/gallon and gas costs $4/gallon and electricity was free, it would take 6.25 years to make up the difference. That extra $10k seems to be hard to justify.
When I talk to friends/family about electric cars, the issue that always comes up is range. These are people who maybe drive more than 100 miles in a day once or twice a year and this is a huge concern. I don't know what happened with Tesla's robotic replacement for battery packs, but until it is common place or cars can travel 1,000 miles on a charge (and can be charged in less than five minutes) or "Mr. Fusion" becomes a reality, I don't see this not being an issue with the public at large.
Maybe we could see the tipping point if the price of an electric car was comparable to a gas powered car but I think it will take lower costs and essentially infinite range for it to happen.