While you are right in that having subscriptions was much common last century. It is my understanding that the field of media studies accept advertising as a central force in the development of mass media.

"With a few exceptions – television in the United States and the free daily tabloid – there are no media which from their very beginning have not used advertising as a source of revenue [...] The influence of advertising on the media development started during the 19th century with the popular newspapers. It was the common interest among media owners and advertisers to reach the masses that connected advertising and media and made them mass media and mass advertising. The productions techniques that were introduced in that century allowed mass circulations but it was impossible to conquer a large audience with the contents of the contemporary elite papers, expensive to buy and hard to read. The contents were changed and the prices were reduced. In order to make them very low, advertising was accepted as a second source of revenue. The papers were sold on the streets or home delivered anything that would bring the papers closer to the readers. In order not to discourage subscription, weekly subscription was introduced."[0]

[0]https://www.tandfonline.com/doi/pdf/10.1080/16522354.2006.11...