Given that capitalism happened this question cannot be answered in a fully verifiable way, so I’m primarily asking for your personal thoughts.
This popped up into my head a while back. A lot of books today are part of a series, standalone books exist but aren’t the standard. It seems like a move driven in part by profit potential, it’s easier to sell a work if it’s connected to a prior work the people are already invested in. Could this still have happened under socialism in your opinion?
Stories existing in the same universe would have happened with or without capitalism. Sequel books are simply a way for authors to expound upon the events in their universe that they may have felt weren’t concluded in the original/needed more than one book to be completed. Think of Homer’s Iliad and Odyssey—two separate works that share major characters in the same general time frame, but that contain different adventures and thematic frameworks entirely. These stories predate capitalism by at least 2,000 years.
The caveat I guess would be book series that drag wearily on beyond their creative, natural conclusion for the sake of profit wouldn’t exist without capitalism, obviously.