For American cities to embrace tiny cars like this, it seems like there would first need to be a revolution in parking, and then a complete reworking of all of our roads. Our infrastructure is in such a terrible state that we rely on the suspensions and footprint of our vehicles to compensate for the condition of our road joints, potholes, etc.
I think speed would be an issue, too. In China you generally move short distances at slow speeds, if you are using personal transportation. If the trip is more than 10 minutes, you take the train. (At least that's how my American friend in China tells it... I've never been there...)
American cities make a whacking great load of money on enforcing inane parking laws and regulations. For example, if I ride my motorcycle into town, I have to try and take up an ENTIRE car parking place, and pay for the entire thing. If I fit my bike into an otherwise unusable nook, or at the end of a row of cars where there is space between the last car and the corner, I get a car-sized parking ticket.
I think American roads and regulations would need to be MUCH different if we were to see an influx of tiny cars. I think it is far more probable to expect Home Depot to have a rental fleet, than it is for Americans to have tiny cars....