By 1959, there were no fewer than 26 episodic westerns per week on ABC, CBS and NBC; discounting syndicated programs, independent local stations and Saturday morning reruns of Roy Rogers, Gene Autry, The Lone Ranger, Sky King, The Adventures of Wild Bill Hickok, Fury, et al.
By 1968, the networks began to lose interest in westerns allegedly due to protests against the Vietnam War, the assassinations of Dr. Martin Luther King, Jr. and Robert Kennedy and intense pressure from the PTA's war against violence. In actuality, the westerns hadn't lost that much popularity with their viewers but the networks, wanting nothing more than to rid themselves of "rural" programming sited the pressure groups as an excuse for the cancellation of the western programs. The main reason was that, while westerns had indeed lost some of the veneer over the years, "demographics" were now becoming the main source for ratings and sponsor appeal instead of the popularity of a program. Sponsors wanted to hit a target audience under 35 years of age - the Baby Boomers.
Other highly rated non-violet programs appealing to the wrong demos included, The Beverly Hillbillies, Green Acres, Hee Haw, The Jim Nabor's Show and Mayberry R.F.D.; even shows like The Red Skelton Show, still in the top ten for CBS, got the ax. Red moved to NBC for one season 1970-'71 where he wasn't treated any better before calling it quits. By 1970, for the first time in 21 years, there were no westerns announced on the regular Fall schedule for the networks.
The PTA had been powerful enough to soften the violence on the remaining westerns such as Gunsmoke, The Virginian (The Men from Shiloh)-Bonanza was tame enough already - and possibly the roughest of them all The High Chaparral, but the intrusion of pressure groups only gave the networks the impetus to cancel the shows that wouldn't fit their agenda.
The "Rural Purge," as it would come to be known, would cripple the western genre and cause the common variety show to cease prospering much past Sonny and Cher and the very popular Carol Burnette Show. Cutting edge humor like The Smother's Brothers Comedy Hour would become a victim of the new counter-culture simply by becoming an outlet for it on national television. The violence and protesting would continue, but nobody wanted to bring attention to it, thus the 35 plus group became excluded; as well as any disgruntled 18 to 25 viewers who wanted something more than the make-believe establishment protests on display on programs like, The Mod Squad.
But the westerns, which had been riding high in network ratings for almost 20 years, were defanged and by 1975, for the most-part, remained of little importance to network brass. The final demise of Gunsmoke, arguably the biggest western of them all, brought to a close the era of westerns as a main staple of primetime TV; Gunsmoke had originally been cancelled back in 1967; the demand for the program's return was so great CBS couldn't ignore this fact and returned it to the 1968 schedule. The weekly Gunsmoke opening of the showdown between Matt Dillon and an unknown gunfighter may not have beaten the marshal in 20 years, but demographics finally did.
However, within 30 years, the very same reason for the "Rural Purge," demographics, would play a major role in bringing western programming back in style for the now aging Baby Boomers...