That is the concern of a new paper by Ray Fair, here is the abstract:
This paper examines the history of U.S. infrastructure since 1929 and in the process reports an interesting fact about the U.S. economy. Infrastructure as a percent of GDP began a steady decline around 1970, and the government budget deficit became positive and large at roughly the same time. The infrastructure pattern in other countries does not mirror that in the United States, so the United States appears to be a special case. The overall results suggest that the United States became less future oriented beginning around 1970. This change has persisted. This is the interesting fact. Whether it can be explained is doubtful.
Is it not the rise of interest in spending more money on medical care?