Narrative has dwindled in importance since the first novels. Compare a novel of a hundred years ago to one today, and you'll see what I mean.
What you'll find is that descriptions, dialogue, and narrative have all simplified.
Descriptions aren't as detailed, and you certainly won't find long pages of descriptions of the countryside, the houses, or the clothes.
The narrative has become more intimate with the author less intrusive. The reader is put dead center into the character's head and thoughts, and the intimacy tends to only be for one or two characters, not every character in the novel.
Instead of omniscient, the current standard in fiction is third and first person. Most fiction is written in warm third person with occasional forays into cold third person. Hot third person tends to be only used in romance which is about emotions.
The paragraphs are also shorter.
The dialogue carries more story weight because it must give the reader more information about what the characters are thinking and seeing as well as advancing the plot.
In other words, much of the fat of the novel has been trimmed because modern readers want only the meat and bone of the story. This trend continues today with the narrative even more spare than it was a few years ago.
The fourth wall is never acknowledged anymore in genre narrative because of the more intimate viewpoint. You will never see this in a contemporary novel-- "Do not despair, gentle reader, for Becky will soon get her comeuppance."
A rare exception is in some chick lit and Buffy lit urban fantasy where the main character "talks" to the reader.
Constantly shifting viewpoints in third person has never been used in fiction except in the romance of the last twenty-five years where a bastardization of omniscient and third person developed more from ignorance of narrative techniques than deliberate choice.
At its best, it is close to the norm of omniscient; at its worst, it is annoying and rather nauseating in a motion-sickness sort of way as the reader is jerked back and forth between two heads and offered considerably more information than is necessary.
Few writers (Nora Roberts, for example) can write well using shifting viewpoints, and it is the kiss of death for most editors when they are looking at submissions because it shows the writer doesn't know what the spit they are doing.
As an interesting side note, video techniques are changing viewpoint. Editors frown at sentences like, "His hand ran up and down her back." They prefer, "He ran his hand up and down her back." Body parts should not act independently according to editor thought.
However, many writers now prefer, "His hand ran up and down her back," because they see this as a close-up in their mental video of the action, and it is beginning to creep into published writing.
In a few years, this type of video technique may be as common in genre narrative as the other changes we have seen.