Are you saying that using a car for commuting purposes vs. some form of mass transit is an indicator of social status to Americans? If so, I would argue that it could be but within limits.  I think a lot has to do with commuting distance and the lack of inexpensive, efficient mass transit, a situation that you note before zeroing in on the social status cause.

I would also look at convenience of having a car at the work place as a reason.  When you live thirty miles from the work place (many do because of the high cost of housing closer in) and the mass transit lines only run during rush hour, early and late departures from the work place are eliminated, otherwise one is stranded at work.  The real mystery to me is why so many people endure the arduous commute here in Washington, forsaking the faster high occupancy vehicle lanes just to drive their cars to work alone.  I carpooled to work here for almost 30 years to half a dozen locations and only drove alone a few times at most.  

I can swear there ain't no heaven but I pray there ain't no hell. _ Blood Sweat & Tears