Through a system of billing specifically set up to make the production company end up deep in the red while the big "studio" rakes in the profits. AKA Hollywood accounting.
The system is rotten to the core, and copyright as a concept has been broken since the day someone could drop a couple of 100s on the table and walk out the door with the digital equivalent of a printing press.
Copyright basically hinges on the act of copying being a laborious process, involving large machinery and man-hours.
This because such requirements make all acts of copying for profit activities, to recoup the costs of the copying.
But when producing one additional copy is a case of ctrl-c ctrl-v, calculating the cost heads into "angels on the head of a pin" territory.