Today's SMBC suggests a positive correlation between automotive ostentation and penis size, by way of wealth.
Captain Capitalism says it goes the other way, at least as far as the wealth factor: the flashy expensive cars are generally bought with borrowed money, and the drivers have very low net worth.
And, thinking back on people I've known who had expensive cars and weren't, shall we say, on the elderly side? They tended not to be all that wealthy... or not to stay wealthy. Overspending on status symbols is actually a pretty good marker for downward mobility.
Yeah, there are some people who really do have gobs of money, and can afford the mansions, luxury cars, and private airliners. The number of wannabees, though, is much greater.