What a good question.
I think that future nature-based tribes (I have trouble w/ the word “primitive” and prefer “nature-based” or “indigenous”) will rely upon written communication much, much less often than we do. But I certainly think that reading and writing will find a certain niche usefulness. I can definitely see it used for communication between tribes, and in certain circumstances within a tribe (as a phase of conflict mediation, for example).
Another question: what kind of transformations can you imagine writing to undergo? Letters replaced by pictographs, like a sign language? When people live in closer connection to nature they will probably prefer to respresent a characteristic of an owl rather than writing the letters o-w-l.