The numbers suggest this is false, for the US at least. The oft-repeated study comes into mind that 47% of Americans can't cover a surprise 500 dollar expense without it being a major worry. See also the fact that the average new car purchased in the US today is 50 grand. I know I'm comparing apples and oranges here but if both those stats are true then it's clear there's likely a large overlap between people who are broke and people who are driving expensive cars.

Aside from that, there's the fact that if you can actually afford it, then it's likely better to finance than to pay cash because you can invest the full purchase price of the car for a higher return than the interest you would pay.