The range of a LEAF is closer
The range of a LEAF is closer to 80 miles, not forty. Even in real world driving. Secondly, charging is easy to come by, even here in the wilds of Wyoming, if you're willing to hunt for it. The Nissan dealership in Cheyenne sells a LEAF a month. I interviewed them about it. You can read that here on Torque News.
The fact is, though, nearly all EV sales are in the "green happy face" comprising the coasts and Arizona/Texas. The vast majority are in California itself, especially for the Model S. It's true that I can buy a Model S and drive it coast-to-coast thanks to the Tesla charging stations, but it's also true that if I can afford a Model S, I probably don't really need the $7,500 as an incentive to buy the car either. I would think that if that's what drives buyers, maybe Tesla's marketing (such as it is) needs to emphasize fuel savings a little more. Nissan LEAFs sell like gangbusters and they do it almost entirely through word of mouth and simple sales floor mathematics offered to buyers. Looking at other high-end vehicles, the resale value of a BMW i8 is actually almost double its MSRP because they're so hard to get. Should we subsidize a $137,000 car that could be resold for over $200,000, adding further profit to the buyer via taxpayer incentives?
Finally, the argument can be made that incentives aren't really working. It's very likely that the EPA will revise its CAFE requirements in the coming months because electrified vehicle sales have not been what they had hoped.