One can imagine the hypothetical scenario where a large filling station network would offer a battery subscription service of sorts, whereby you can stop at a station, swap in a charged battery, and drive off.
You just change the service/self-service oil option with the self-service electric vehicle battery switching option.
tintin, what is the difference in the logic behind 'afraid of not getting home' with regards to combustion and electric motors? Both run out of juice at some stage, you just make sure it doesn't run out right.
Also I doubt our electrical infrastructure will support large-scale EV recharging. We have brown-outs and black-outs now in many urban areas during peak demand times. So we'd at least need "intelligent grid" capability to throttle or disable vehicle charging during peak demand hours.
Finally the whole issue of road tax is never discussed. This is a significant portion of the retail cost of gasoline. If/when large numbers of people switch to EV cars, we'll need a way to meter and tax the electricity for road maintenance, or find another way to fund that.
It's pretty clear that a large scale switch to electric would require us to upgrade the grid, make available metering solutions and add tax the electricity. It's not going to be easy, but it's not going to be impossible either. And the transition is likely to happen very gradually. 150 years ago people likely told the first auto makers the same thing: How are people going to buy your product when there it's so difficult to get fuel? The problem was solved piece by piece as the market demanded cars.
b) The batteries are shaped to the car[1]; standardizing batteries would require sacrificing car design (aka: goodbye back seat).
[1] From http://www.teslamotors.com/models/features#/battery "...integrating with the vehicle in the same way, providing structural, aerodynamic, and handling advantages."
[edit] Wikipedia claims this, but their reference no longer exists on Tesla Motor's website. Searching everywhere in the OP yields nothing about this.