I think what the auto makers should have done is make cars more of a need than a want. That'll promote some business
Far be it from me to imply that economics might be slightly beyond you, I think you might not quite understand the subtle nuances of needs and wants. It's fair to say that a car, as a purchase, can be classified as a "need" for most people anyway. Simply by producing cars, manufacturers are catering for consumers' "needs".
To add to this however, manufacturers present a range of cars that then cater to the consumers' varying tastes, and these different designs and features are geared towards what the consumer
wants (or what the manufacturer can make the consumer
think they want, which is where marketing comes in).
Either way, a company can't make the car
more of a "need" because they are already. However, those people who already have cars are now less inclined to replace them as it becomes uneconomical for them to do so. Couple this with a situation such as the high fuel prices last summer, and a manufacturer that survives on bread and butter cars that offer nothing special and maybe have high fuel consumption (step forward, Big Three) and you get stockpiling, because people make rational decisions based on their wallets instead of irrational decisions based on their "wants".
Only
now, the market has slowed down so much that even marques like Land Rover and Jaguar (as in the images) have actually produced too much, when in the past they've struggled to meet demand.
[/economics 101]