Final answer:
The American economy changed from producer-durable goods to a consumer-goods economy due to the increasing number of middle-class Americans who had the money to buy products, the introduction of new products and planned obsolescence, and advances in credit.
Step-by-step explanation:
The American economy changed from a producer-durable goods to a consumer-goods economy due to several factors. Firstly, the increasing number of middle-class Americans who had the money to buy products fueled consumerism, where the purchasing of material goods became a preoccupation. Secondly, new products were introduced in response to consumer demands, and planned obsolescence was implemented, which encouraged people to replace their possessions more frequently. Lastly, advances in credit, such as the birth of credit cards and installment plans, allowed Americans to confidently spend their money on consumer goods instead of saving it.