Again, I think there are two different issues at play with the Tesla and the Leaf, both of which suggest that widespread adoption and production of EVs is some distance away.
The issue with the Tesla is that it isn't just any old electric car: it's one of the very best cars in the world. It has cachet, confers status (for both pricing and availability reasons), incredible performance, real utility, and it's not hugely more expensive than a comparable car like a Porsche Panamera. It also enjoys tax credits in theory, but this is a marginal issue given the price of the car and the low likelihood that the owners will have an income low enough to actually use it. This is a difficult business model for anyone to emulate, and the pricing will necessarily limit the potential market. It's not until Model E that we might get the Tesla experience in a more affordable package that will have broad appeal.
The second issue, related to the Leaf, is that it sold like crap even though it had a tax credit that effectively chopped $7,500 from the price. Nissan had to chop another 18% from the price in order to get the sales they were hoping to get. So basically it seems like these cars should (in a subsidy-free world) be selling for more than $11,000 more than they are, and it's doubtful that Nissan sees much, if any, profit from the Leaf. So people are essentially paying only 2/3 of the actual cost of a Leaf, and it still doesn't sell a lot. That doesn't sound hugely promising to me, unless we expect the government to indefinitely subsidize electric cars through tax incentives.
I'm sure electric sales will continue to increase, but at the low end it will be motivated by car companies willing to eat losses in order to build market share, reputation, and expertise. And for all of them they're likely to appeal only to those purchasers who have another vehicle for long-distance transportation.