Don’t think enough people will buy them to make a difference. Do the math. Volt with tax credits cost about $35,000. Regular car, about $18,000 that gets about 20 mpg. So you save $17K and at $3.5 per gallon avg. over the next several years, you can buy about 4,800 gallons of gas or go about 96,000 miles before you break even. Just saying.
You’re also not adding in the costs of the batteries for these things. On the Prius, a replacement battery currently costs @$2500-$3000. (Although I hear the price is supposed to drop down to around $2000.) Guess what? Here in Arizona, I just had to replace a regular old $80 battery last weekend. I got a year and a half out of it. So I always buy the warranty because in this heat, batteries do NOT last, and you can be guaranteed that a $3000 battery will not fare any better.