> In the earliest days of getting people to pay for cable TV when OTA was free, the pitch was that you'd see fewer/no commercials.

No, it was quality of reception, especially for people who were farther from (or had inconvenient terrain between them and) broadcast stations; literally the only thing on early capable was exactly the normal broadcast feed from the covered stations, which naturally included all the normal ads.

Premium add-on channels that charged on top of cable, of which I think HBO was the first, had being ad free among their selling points, but that was never part of the basic cable deal.