> why wouldn't you assume that it's going to continue to do so?
Because of the increasing difficulty (and thus cost).
The first 5% was easy and (relatively) cheap to equip, from there it goes uphill, and becomes steeper and steeper: Putting an outlet on every mall parking spot (for instance) will be too big an investment (installation, energy capacity, etc.) and will probably never happen. Or they will start billing the parking time in hope to recoup their huge investment in the usual 2 years time (meaning it will be cheaper to go shopping in a private helicopter...).
Biting the hand that feeds IT
