There are many reasons why only one had to work in the 50s, yet often two must work now. Part of the issue is that now many families of 4 live in houses that are much bigger than in the 50s. Houston is filled with mid-century modern style homes that are around 1500 sq ft. These are now being knocked down to build 2500 to 4000 sq. ft single family homes. Of course, the other reason is that salaries have not kept pace with inflation, so now two people work, and many families need two cars, or more once teens start driving (poor public transit here in Houston). The lack of rising salaries led to credit cards. Since the economy depends on constant consumer spending, banks figured out that they could just loan consumers money to spend, since they weren't being paid enough. Of course, all of that credit card debt is just more money created out of thin air. At some point, it must all come crashing down. In theory, fractional reserve lending provides an elastic money supply that helps grow value, but with consumer debt and predatory lending, the loans are not backed by much value, hence the problem.