Jay Leno predicts demise of vehicles running on gas.

I think so too, eventually. However, it won't be for quite some time. The current fleet of battery/electric vehicles, while amazing, are still fairly limited. Infrastructure isn't there yet and won't be for some time.
Personally, I think we'll find ways to crack water cheaper and easier and run vehicles on hydrogen before we figure out all the hurdles to pure electric, but that's just me.