You raise some good points, JL, but I think your argument falls short in several ways.

First and foremost, you conflate fiction with screenplay, two very different genres. What makes a villain work on the screen is not the same as what makes for a compelling antagonist in a novel. Both genres involve stories with characters and plot, and both require a writer, but there's not a lot of overlap in the factors by which their quality is judged.

Second, you make no distinction between sci-fi, action adventure, fantasy, horror, psychological thriller, and drama. Few would argue that all of those genres (especially on the screen) require extensive character development, even in the heroes.

The writer of novels, especially in the "literary" genre, needs to create characters with sufficient depth to keep us interested. Since your reader is usually going to identify with the protagonist, you have to work a little harder to make sure your antagonist has motives other than the fun of being evil, just as you have to show your hero to be something more interesting than a do-gooder.