Fictional universes are all the rage these days. Marvel, DC, Harry Potter, the Cosmere, and those are just some of the biggest.
It’s easy to see why from a writing standpoint: Flow and Marketing.
What do I mean by Flow? For a writer, it’s hard to start from scratch. It’s infinitely easier to write something familiar. Hence why fanfiction is so huge. Some authors thrive on new worlds and new characters, but I would wager that most don’t. Most would rather continue to follow proven characters in familiar worlds. And for an author, it’s easier to write five books in a series than it is to write five standalone novels. After the first book in the series, a lot of character building and world building is already done!
What about marketing? Well, this part may come as a surprise to all the non-writers out there. Do you know why series are all the rage these days? Why is the Fast & the Furious is still going? Why does it seem like there’s a bunch of the next fourth or fifth of a series coming out? Because it is cheaper to market a series of five books then it is to market five standalone books. I market the first book and make money as the reader buys the next four books in the series. With standalones you have to sell five separate books.
So, any surprise why fictional universes are all the rage these days? It’s both easier to write in a universe and cheaper to market.
Not saying that fictional universes are the end-all, be-all of story-telling. Just making an observation.