There were so many that they had to be distinguished by cool catchphrases or personal quirks.
Kojak sucked a lollipop and said "Who loves ya, baby?"
Cannon was overweight and a gourmand.
James Rockford lived in a trailer with his Dad.
Baretta (1975-78) was distinguished by his massive biceps, his cockatoo named Fred, and his two catchphrases: "You can take that to the bank!" and "That's the name of that tune!"
"Keep your eye on the sparrow, when the going gets narrow."
Two Biblical references -- God keeps his eye on the sparrow, and the narrow road leads to salvation.
I didn't know what it meant, but it was catchy.
Surprising for someone over 40, Robert Blake got substantial attention from the teen magazines. Maybe it was the beefcake, unusual for a 1970s cop show. In Sweden they even sold paper dolls for kids who wanted to play dress-up with Blake in underwear.
Apparently there was a gay-positive episode in 1977. At least as gay-positive as tv got in the 1970s. Baretta befriends a gay teen hustler (Brian Miller) who witnessed the murder of his coworker.
However, his autobiography, Tales of a Rascal, has many stories about befriending gays and bashing them, making homophobic slurs and speaking out against homophobia: "All of show business owes its entire life to the gay community. What is that line from Boys in the Band? 'Why does it take a fairy to make something beautiful?'". He got the quote wrong, but the sentiment resonates, along with the stereotype.
Robert Blake has had an interesting life.