You're describing a post-scarcity economy, which we have now for information and media. And we have enough productivity now to provide for the basic needs of everyone in the world.
The reason why we still have advertising and why many people are lacking in their basic needs, has to do with human nature and power. A significant minority of people seek power and control over others and they are artificially maintaining scarcity in order to maintain control.
This is why we still have advertising. The advertisers want to control the content of the media in which they advertise. Formerly advertising was about selling products and services, but that doesn't happen much anymore -- now it's mostly about control. And those who want to control others will sabotage any efforts that attempt to undermine the system they use to exert that control.
This is why systems / networks / communities that are developed which are not ad-supported or otherwise locked into the current economic system often fail -- because they are sabotaged by those who want to maintain the current status quo.
It takes a lot of planning and effort to design and build a network or community that can withstand such attacks by those incumbents.