"Greed" isn't the answer - we have greedy companies in every area of the economy, yet somehow the prices of phones, computers, desks, large appliances, televisions, and many other types of goods hasn't skyrocketed in the same way as cars.
What makes cars different? I know that the cost of labor has significantly increased (which partially motivates the stratospheric increases in education and healthcare costs), but I thought that cars were mostly manufactured in an automated manner.