It goes back to the days when the thought of paying for TV seemed unthinkable. Yet HBO was the first really big cable subscription service and it's still around today. According to the linked article, which I found very revealing, the home movie outlet derived a philosophy that emphasized how it was different from regular network television - and why it was worth those extra bucks. 

"In 1996, each of the four broadcast networks rejected David Chase's idea of a mob boss who goes into therapy. A top CBS executive said the therapy made him look weak. A Fox executive thought a violent mobster would be a turnoff to advertisers. By the time David Chase met with HBO, in February 1997, he was expecting much the same. It couldn't have been more different. "Lean harder into the mobster in therapy angle," they told him, and "go ahead, shoot the show in New Jersey. It'll be more expensive, but it'll look real."

5 things HBO did early on to dominate TV, and what other networks can learn from it