That said, they're also not uncommon - a quick look at registration data suggests ~8% of cars "on the road" are BMWs, though of course just because a car legally could be on the road doesn't mean it's being driven with any regularity (I had a co-worker years back whose pastime was buying old BMWs and fixing them up; apparently they could be had relatively inexpensively at the time, as servicing was pricey).
Which is why all this pedantry misses the point: there's nothing terribly special about BMW; total cost of ownership is probably higher than domestic brands, but you could just as well pad out your ordinary expenses with a Ford or GM payment; a new Suburban or nicer pickup can soak up just as much excess cash as that X3.
Then again, Real Americans drive increasingly old used cars.