Let's start with $5 a gallon gas and make the assumption that gas goes up a $1 a year for the next 7 years (which is when the batteries would be scheduled to be replaced). At the end of 7 years (with $11 gas) the gas car is still $760 cheaper and you wouldn't have to pay the estimated $3000 fee for battery replacement. $3760 loss over 7 years. Sounds like a loser to me.

As for helping the environment, I don't think lead, nickel, lithium and highly caustic acid are considered "environmentally friendly."