In America, the ‘Golden Age’ existed from the 1950s to 1970s. There was no cable or Internet to offer alternatives. The commercial basis of the programmes, that is the advertisements which interrupted the flow of the programmes, was how the stations made money.
There were only three stations of note; ABC, which aired on Channel 7, NBC which was Channel 4 and CBS which was Channel 2.
There were other stations depending on your locality. In New York City, for example, there was no Channel 1, 3, 6, 10 or 12. Channel 5 was local and aired reruns as did Channel 9 and 11, where Channel 13 was to be ‘Educational’.
The three major stations focused on competition with each other to an almost warlike nature.
If one had a Western at 7 pm on Saturday, so did the other. If one had a medical show, i.e. Dr. Kildare, the other had Ben Casey. If one had a space show; Lost in Space, the other had Star Trek.
As each ‘season’ began’ in September and went to May, the months of June, July and August were full of re-runs which allowed the viewer to visit the other two stations as they had already seen this episode of their chosen production on their usual station.
What happened, sometimes, in watching a rerun of a show one had never seen, would be the kind of repetition of a story line already viewed.
Hence, if in Western One there had been an episode where the main character met a possible love interest who died before conclusion, the same kind of plot would appear in Western Two.
In some cases it seemed a matter of a basic idea in other a kind of ‘commercial spying’ as if the script of Western One had been ‘leaked’ to the producers of Western Two and they decided to make it bigger and better.
There was a lot of duplication, i.e. “Wanted; Dead of Alive” with Steve McQueen was the story of a Bounty Hunter. In Have Gun, Will Travel, with Richard Boone, it was a gun for hire.
Many of the actors were ‘confined’ to one studio so that the performers would go from one ABC production to another, as if they were legally barred from being seen on NBC.
As time passed, and there were more stations and Cable became popular, and more innovations arrived, the need to compete didn’t depart in the twenty first century.
This station has the Forensic CSI and that one has the Forensic NCIS; both of which have spin offs, so that although beginning in Las Vegas and Washington, D.C. there were other CSI in Miami and New York City, as well as NCIS having a branch in Los Angeles.
The competition does not end in America, for as one knows there is Sherlock vs Elementary, two different versions of the Sherlock Holmes stories, one set in London, and a British production, while the other is set in New York City and is American.