This is kind of how I feel about the idea of the very first writing being chiseled in stone or engraved on clay tablets.
If there was a much older civilization that never did that but invented paper and pencils instead, we'd probably never know it.
Writing on the ground is probably No. 1 then maybe carving with a stone into wood/bark as No. 2 but yeah, lots of stuff we will never see or know about because they werent preserved.
Or because it's not immediately recognizable as writing. I wonder how long it would have taken archeologists to figure out the quipu was actually a knot-based writing system without the Spanish mentioning their use by the Incas in their records of the invasion.