Money is in the design. Value is in the range.
The battery in the Tesla S is much bigger, but Tesla pulls it off while building the Model S less than 200 lbs heavier than the Chevy Volt.
At least the Teslas performance is worth the extra money. You can see some value in the premium price.
A high end Tesla S will run about $77,000 or $240 per mile of range.
By comparison the Volt is badly over priced. At $40,000 or $1,142 per mile of range is is more than 4 times the cost per mile of range.
If I had the money to burn on an EV, it would be a Tesla. Hands down it is a better value.