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?