I don't think saying "120v isn't enough, you need to rewire your entire house" is really accurate either. Most water heaters, stoves, and some central heaters run off a merged breaker for 240v. You can easily use one of those lines for the car if you don't plan on taxing the thing the entire time (though I figure if you have 50k for a car you have 1k to add an extra circuit and wire your garage up for it).

Also, 240v cars makes so much more sense in a world where 99% of people use 240v outlets, and in the US you can just oscillate two 120v's and get a usually-good-enough 240v signal.