The "Rural Purge" of American television networks was a series of cancellations in 1971, of still popular rural-themed shows and shows with senior citizen skewed audiences.
The purge was instigated by CBS executive Fred Silverman in 1971, following research highlighting the greater attraction to advertisers of the more affluent younger urban viewer demographic and the institution of the Federal Communications Commission's Prime Time Access Rule, which led to the loss of a half-hour of network programming each night. While it is most commonly associated with CBS, ABC also followed a similar pattern.
Silverman, disturbed by CBS's reputation as the "Country Broadcasting System," decided not to renew a number of both long-running and short-lived shows that were either rural oriented, or had a low youth/urban demographic: The Beverly Hillbillies, Mayberry R.F.D., Green Acres, Hee Haw, The Jim Nabors Hour, The Ed Sullivan Show, Family Affair, and Hogan's Heroes were all cancelled after the 1970-71 season.
While many reference books and websites claim that all or most of the canceled shows were still enormously popular when they were axed in 1971, this is something of an overstatement. Nielsen ratings for the 1970 - 1971 season show that most had actually fallen out of the Top 30. The highest rated of the shows to be cancelled were Mayberry R.F.D. (at #15) and The Beverly Hillbillies (at #33, down from #18 the previous year).
ABC was also looking for younger demographics, and in May 1971 canceled the long-running The Lawrence Welk Show which, like Hee-Haw, transitioned to first-run syndication where it ran until 1982, as well as The Johnny Cash Show.
Silverman replaced much of the canceled programming in 1971 and 1972 with urban-oriented, "relevant" fare including highly acclaimed shows such as All in the Family (and its many spinoffs), The Bob Newhart Show and M*A*S*H. Added to the schedule the previous year was The Mary Tyler Moore Show. Under Silverman's watch, game shows returned to the network's daytime schedule during this period as well, including The Price Is Right, which debuted in September 1972 as replacements for reruns of 1960s prime-time sitcoms such as The Lucy Show and Gomer Pyle, USMC.
While younger audiences are favored by advertising agencies for their impulsive buying, syndicators are less apt to write off older demographics, as they tend to have more money, and are usually less fickle/more loyal in the long run. (see Too Close for Comfort, and Mama's Family, both syndicated after network cancellation).
Note that some of these shows did not have a rural theme.