I think there are two categories for ‘inciting incident’, which is that they exist for the full story arc (such as when lovers meet in a LS) but they also exist as the (usually) first story element in a scene or sequence, and in almost all of them. So there are inciting incidents all throughout a novel.
A good place to get a handle on this concept is Story Grid.
And you honestly don’t have a story if you don’t have one, including the full-arc story as well as the encapsulated story-like moments inside scenes. It is essential. Story does not work without it.
Also, it is very difficult to write a compelling story or novel or even a sequence or a full scene without the inciting incident preceding the other story elements, which usually follow in the order: progressive complications, turning point, crisis question, climax, and resolution.
There are other ways to do that, but none really work well.
As to when to have the full-arc inciting incident, one of the ways to have things work nonlinearly with regard to the timeline is in medias res, which means starting a story or story event or scene or sequence in the middle and then flashing back to explain it by showing the beginning (which usually includes the inciting incident) a bit later.
That confused readers in 1800, but today it is so common that it is more common than having a strictly-linear timeline.
But to simplify, for the sake of argument, let’s assume your story is fairly linear, adhering to cause-effect. In my experience, when I see the inciting incident as the very first thing, it sort of leaves me cold.
My opinion, and this is just an opinion, is that a good story can’t be just plot, and that the best stories concentrate also on character. So even in a very plot-driven thriller, for instance, I think the first thing you want to do is establish the MC. Make them likable, admirable, and interesting, and give them an issue that draws empathy. IOW, get the reader to bond with them. Get them to care.
For instance, in the thriller ‘The Silence of the Lambs’, the first thing that happens is that Thomas Harris introduces the MC, Clarice Starling, and then gets the reader to bond with her. Only then do we get the inciting incident, which is her boss sends her on an assignment to speak with Hannibal Lecter.
The point here is if the reader doesn’t care about the character, the reader will hardly care about what happens in the inciting incident. Once they are invested, they will care.
This does not imply that you can’t use the inciting incident as the problem that causes the MC to draw empathy, you can. But in my opinion it’s best to get the character and the reader to bond first, then go directly to the inciting incident.
I have seen stories begin with good action scenes or sequences that seem almost wasted because the author has not yet got the reader to bond with the characters first.
Readers put books down for 2 reasons: 1) ‘I can already predict what is going to happen’, and 2) ‘I don’t care what is going to happen’. Make them care early, if not first. Then, tell their story, which typically begins with the inciting incident.