Cable TV started as a way for people in mountainous areas to get signal to their sets ... not as an ad-free alternative to broadcast TV. At the time, over-the-air networks were received by the cable TV companies and sent down the wires (coaxial cable), so the reality is that the subscribers were paying for free television when they couldn't receive the signal directly at their location.
That was definitely the case for early cable, but at the point where it was receiving wide adoption one of the main selling points for non-isolated customers was premium cable-only channels, which at the time were generally ad-free or very sparse with adverts. Broadcast channels always had adverts, but those weren't the selling point for wide adoption.
A lot of specialty and news content that used to be ad-free or relatively low-ad-content isn't anymore, but this also isn't really relevant to my point and I never said that cable used to be ad-free, but rather that there used to be a more prominent attraction to it due to some ad-free content offerings.
That ad free content still exists - HBO and similar channels. The same content that was originally ad free.
But now, we are actually in a golden age of having ad free content for TV.
Of course you have Netflix, Amazon Prime etc. But you also have Hulu’s ad free tier that offers content from NBC, ABC, and the Fox networks without ads and you have CBS All Access. You can also get ad free content from AMC.
Someone has to pay for the content. If you are willing to pay for ad free video, there are plenty of options.
