Why did car ownership rise in the postwar years?

could someone give me a brief explanation

you : )

It is a combination of factors, including new technology and the transformation of the American manufacturing economy, from producing war-related items to consumer goods at the end of World War II. By the end of the 1950s, one in six working Americans were employed either directly or indirectly in the automotive industry. The United States became the world's largest manufacturer of automobiles, and Henry Ford's goal of 30 years earlier—that any man with a good job should be able to afford an automobile—was achieved

The 1950s were pivotal for the American automobile industry. The post-World War II era brought a wide range of new technologies to the automobile consumer, and a host of problems for the independent automobile manufacturers. The industry was maturing in an era of rapid technological change; mass production and the benefits from economies of scale led to innovative designs and greater profits, but stiff competition between the automakers. By the end of the decade, the industry had reshaped itself into the Big Three, Studebaker, and AMC. The age of small independent automakers was nearly over, as most of them either consolidated or went out of business.

A number of innovations were either invented or improved sufficiently to allow for mass production during the decade: air conditioning, automatic transmission, power steering, power brakes, seat belts and arguably the most influential change in automotive history, the overhead-valve V8 engine. The horsepower race had begun, laying the foundation for the muscle car era.

Evaluate the reasoning Douglass uses in the passage by determining whether the conclusion is valid or invalid.