Out of curiosity, how much does it typically cost to charge, say, an iPhone5? For some (many?) doubling this price might not be as much of a non-starter as you think.
No clue how efficient typical USB charging is, the AC-DC conversion is at around 80%, then you've got the battery chemistry which cursory research seems to peg at around 80% efficiency as well. So lets say it's about 1c per charge, at EU power prices.
Doubling is an underestimate. It's more like a factor of 10.
Still, multiplying the cost of charging an iPhone by 10 isn't bad. And in fact you can buy a lot of solutions that enable this, because you're right, it's not a big deal for a lot of people, and the convenience is worth the cost.
For an electric car, increasing the charging cost by a factor of 10, or even a factor of 2, is a much tougher proposition.
No clue how efficient typical USB charging is, the AC-DC conversion is at around 80%, then you've got the battery chemistry which cursory research seems to peg at around 80% efficiency as well. So lets say it's about 1c per charge, at EU power prices.