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?

That’s a great example! As far as I understand the history of that novel, it was written deliberately to be mass produced in the printing press as a commodity to be bought and sold and the novel itself is a critique of feudalism by showing how the Don goes mad trying to live by a code of honor in a mercantile world ruled by money.
So would Don Quixote have even been written at all without capitalism?
Hmm, Probably not. You’re not going to see Cervantes publishing under feudalism, but you’re probably not going to see socialism directly develop out of feudalism either. Im not sure you can have an industrial feudalism w/ mass printing for long, the material conditions that make feudal power structures possible would collapse it into capital accumulation.
Although given the hypothetical, with a wide enough distribution of mass publishing, i still think you’d see book series appear. Authors can be prolific and if the barriers to publishing are low enough i dont see why they wouldnt. Copyright may be signifacantly altered tho. Probably see way more retellings and readaptions of works in a way thats been cut off for the last century & a half.