Makes me wish I had my spreadsheet handy. Still...
$20k Camry vs $30k Tesla BlueStar.
Price difference: $10k.
Assumptions: $4 gasoline, $.10 kwh, 15k miles/year,
The Camry is listed as 25/35. If you drive mostly highway and would get 35 with the Camery, you'll use 429 gallons a year, and the EV would save you $1,264 a year in fuel costs alone. More if you can get free charging somewhere, like at work. Still, you're looking at just shy of 8 years to break even(car is expected to last twice that, but odds of needing a new battery go up) If you're a nasty city driver, you're closer to $2k, and you should 'break even' just after 5 years.
If gasoline goes to $5/gallon, you break even at 6 and 4 years, respectively.
One of the 'tricks' with electric cars that make them 'better' suited for the luxury market is that more powerful motors tend to be more efficient - despite being far heavier and more powerful, the shorter ranged model S effectively uses the same amount of electricity per mile. In other words, put in an engine powerful enough for luxury sedans and you also get great efficiency. You also have the potential for smooth acceleration, no shudder, no gas fumes, no needing to pull into smelly stations for a fillup, etc... It's cheaper(and more profitable) at this time to 'finish' dolling the vehicles up and sell them to rich people. That helps pay a startup to continue developing a truly economical vehicle.
Consider how much effort goes into a luxury sedan to make sure the engine's vibrations and noise(beyond a carefully selected amount) don't make it to the passengers. No real need with an EV, so there's some money saved to allow it to compete with the expensive vehicles. They don't worry about it that much with a Camry level vehicle.