Electric car advocates continually make the flawed argument that because an electric car can have a daily range of 200 miles or so, it can replace the gasoline car for most users. This isn't true at all. People pay for gas cars not just to be commuter appliances, but to have transportation flexibility. Flexibility matters to a lot of people, even if they don't use it, it matters. It's nice to know that if I wanted to, I could drive my gas car the 790 miles to my in-laws house, or 200 miles to my brothers, or 500 miles to my aunts and uncles. It my cheaper for me to take a plane to go by myself, but, add a wife and a couple of kids, then my transportation cost for each trip is about $100-$150 in fuel and my time in driving.
So, with that in mind, I think the real tipping point for electric vehicles will be total operating time on a charge. That means, I want to be reasonably able to drive 10-12 hours on a long road trip with perhaps an hour time for charging. Once that happens, then electric cars will take over for everyone.
With that said, in a married family, having two vehicles, one for road trips, an SUV, and a daily commuter that is electric, makes a great deal of sense. But most families are going to have that "one" vehicle.