First, novels are generally solo ventures. Sometimes there are two people. So there's no corollary of novels written by hundreds of people in collaboration.
Second, novels are strictly in the art category. We're used to thinking of solo artists. Even in fields like filmmaking, which require massive amounts of collaboration, we still view it as an art form and gravitate to the "author", i.e. usually the director.
By contrast, software isn't commonly seen as an art form. There are aspects of art to it, but a lot of it is more like engineering and problem solving. We're used to thinking of teams coming together to solve problems.
Third, no one thinks they're going to strike it rich writing a novel. The odds are almost like winning the lottery. So we instinctively understand that writing a novel has some value outside of the revenue it might generate for the author.
By contrast, the popular story about developing apps is that the only reason to do so is to strike it rich. We don't commonly see the writing of apps as inherently valuable in it of itself. We tend to think if it doesn't make you a millionaire, it was a waste of time. On the flip-side, since many people can't conceive of why you would develop an app unless it's to get rich, they can derisively view the whole effort as a get-rich-quick scheme.
To be clear, I'm not saying these viewpoints are correct, simply that they exist and are common.
I think it has to do with art vs. utility.
I imagine that, likewise, people would care less about the author of a programming language manual, or about the author of their car service manual. It's still writing, but it's writing that is meant to fulfill a useful function. Does the manual adequately describe the programming language? Then who wrote it is irrelevant.
With novels, people are not looking for utility but for enjoyment, for entertainment. And if they enjoyed one author's book, they suspect (often rightly) that they will enjoy another book by the same author.
Now, I personally have some favorite authors in the technical world too. I am thrilled and shouting "take my money!" if I see something new from Guy Steele, for example. But I think that's a bit unusual, and I would happily buy a new programming book written by someone that I've never heard of, it the content looked like what I was after.
Why is it more socially acceptable to be a solo author? I might offer that part of it is ongoing maintenance. It is not typical for a novel to have multiple revisions once it's published. I mean, sure, maybe corrections for typos or something, but we're not going to see a completely overhauled new release of a novel every couple of years. The author does the work, completes it, and it's done.
With software, there's more expectation for ongoing work. If you as an individual were to move on to something else, and not continue working on the software, then an application you wrote in 2023 might become irrelevant and unusable in 2025. Not so with a novel.
Through reading novels I get to know the author. I hear their intimate thoughts and can try to place myself at their point-of-view. It's like talking with a clever conversationalist.
I can't see anything like that ever going on with games. Games work on actions, whose meanings are limited to the state space within which the game is conducted.
Writing is a form of human relationship, and relationships work on love. In writing - even this writing - I find myself always considering you, the reader. I try to become you, in a sense, so as to anticipate your responses. Therefore, writing develops my compassionate skills. Maybe that's what makes writing a more socially important thing.
EDIT: I feel like I'm getting downvoted so much because I wrote Jane Austen as an "old master" novelist and it's triggering hacker news dwellers who hate Jane Austen novels. Or maybe they think I'm channeling Roger Ebert to say that their favorite video games aren't art. I'm not saying that guys.