In the South Bay part of the Bay Area, they are like 1 out of every 10 cars.
When I wash my Model S in the driveway, people walking by will often come up to tell me how much they love their own Tesla's (or wanting to know how I like mine). Never had that happen when I wash my Audi :) The Audi is even the more expensive car.
That to me sound like something one should take seriously because it shows that robust network effects are in play. A few people buy an EV and have no problem with them, that induces more people to consider them as a valid option.