Political theorist Scott Yenor, writing in the Public Discourse, takes a long-view look at marriage, and examines how various political and philosophical trends have had an effect on it:
Family decline appears to be inevitable when viewed with a long perspective. The family has been progressively differentiated from institutions that now accomplish what was formerly within the provenance of the family. The city's gods, and eventually the Church, replaced ancestral gods. The marketplace, and eventually the modern economy, replaced the family as the unit of economic production. The city replaced primitive patriarchy. Slowly, and more controversially, the state has come to fulfill increasing portions of the family's educational mission. Even the family's "provision of social services" has come, more and more, to be a state concern.
This "loss of functions" is a rational application of the division of labor, as functions extraneous to family life devolve in the presence of institutions better suited to accomplish these goals. As the family loses more and more functions, its purposes become thinner but, it is hoped, truer to the reality of what a family is.
This stripping of functions is also, however, cause for serious worry, for the functions of the family can almost always be exported to other institutions or arrangements or the need for them can seem to disappear from human life altogether. We must know what constitutes the family's end or purpose lest we face the ultimate in family decline.