Temporary "production" companies are setup by Producers for the creation usually a single film or series. When filming is complete, these companies are sunset, and cannot have recurring revenue.

The Producer gets funding for their project from distribution company (Paramount, Disney, etc). The distribution company is the long-lived company that recurring revenue has to go to.

The distribution companies work as a cartel, whereby they have an existing revenue stream from all the product placements in existing films/tv that they want to protect. So as part of the Producer's contract with the distribution company, they must get the permission of the distribution company to include branded products in their films.