This sounds stupid but I always thought there weren't commercials for channels that you actually pay for? That the advertisements were to compensate for channels that didn't cost anything?
I haven't really watched tv since the mid 90's and never in the USA so I might miss something obvious here. But where I lived, regular channels were broadcast nationally over the air and they had commercials. I always thought the popularity of cable/satellite subscription was based on you getting rid of the commercials, not paying for seeing more commercials on more channels?
Unfortunately, that's incorrect. The cable channels, as mentioned upthread, early on promised "since we can restrict access, unlike broadcast, we can just charge people and we won't show ads." That's not true in 2012. It is extremely, extremely rare to find television without frequent and intrusive advertising. HBO has less toxic advertising practices and better content, which is why you see them mentioned so often in this context.
I haven't really watched tv since the mid 90's and never in the USA so I might miss something obvious here. But where I lived, regular channels were broadcast nationally over the air and they had commercials. I always thought the popularity of cable/satellite subscription was based on you getting rid of the commercials, not paying for seeing more commercials on more channels?