Your standards are low. Americans own over 1.2 cars per driver. So a 2-driver house has 2.4 cars, or about half of all 2-driver households have 3 cars.
With the statistics as they are, it seems you are the one that's out of touch.
No... You are misunderstanding what they mean by vehicles per licensed driver. Taking a look at Wiki (https://en.wikipedia.org/wiki/Passenger_vehicles_in_the_United_States) licensed passenger vehicles includes Vans, Trucks, cars, etc. a good percentage of which are used for business. In other words, the average family does not have 3 vehicles as you are arguing, but actually 2 or less. The difference is made up by vehicles owned by small businesses, farms, etc. for specific business use. If you dig deep, you'll find that the statistics do not mean what you think they mean.
Secondly, this says nothing about how much the average family pays for cars. Most families that I know have an older car that is used for the daily commute and a bigger hauling vehicle to ferry their kids around. The cars that they do own are valued less than one Tesla. They couldn't afford, either financially or or opportunistically, swapping two cars for one Tesla.