I think this comment really nailed it:
I never understood the program. If I lost my job, I'd still need a car to drive to interviews.
while this is definitely a marketing angle for them, not everyone would still need a car to drive to interviews, and not everyone could necessarily still afford a car if they lost their job.
Certainly not everyone would still need it and be able to afford it but the fact that many people would still need their car helps to explain why so few Hyundais were returned.