> However, I think that China has a significant advantage versus the U.S. — they are primarily selling very small vehicles for intra-city use

This doesn't really matter that much. The average car commute in the US is less than 40 miles per day. Even if we assume that everyone gets a fairly giant Model X, that's still around 12kWh of energy per day.

You can get that much power from a regular 120V wall plug within 8 hours.