For EV to replace cars you need to have superchargers along the main roads (already getting there) for long trips and also some place for visitors to charge in small towns (either superchargers or chargers at hotels, campgrounds, rest stops, etc.

There will still probably be areas of the country where it will be hard to find charging stations (although gas stations are infrequent in those parts currently, its much easier to bring some extra gas in a can then an extra battery).