You might be thinking of counter-signalling on one hand. On the other hand there are just different groups of social status as well. To one group, a mercedes might be very impressive, to another it might be your time spent overseas, even if you all make the same money.

I think the reason cars might not be a reliable status symbol anymore is debt. If someons is in my socia-economic group but driving a very expensive car, it signals to me that they loaned the money so that they could have the status symbol.