"...I misunderstood your intentions!"

Perhaps not. Perhaps I disregarded your specification that Joey live in a cave to reinforce the main thrust of the OP that our image of cavemen has always been false. Humans, including pre-sapiens, have always been relatively civilized, practiced agriculture, lived in villages, but we have no evidence because, as you point out, the artifacts are too soft and squishy to be preserved. It is extremely rare that fossils or artifacts are preserved and only happens in very rare conditions, such as the two interlocked timbers in Zambia being in such a stable and oxygen free environment that no earthquake wiggled them apart, and they were several orders of magnitude less decayed than is usual. Preservation of fossils is always only through very rare conditions, so we have almost none of the massive mountains of bones all the dead have been, because that bone has rotted. Same with wood, leather, wool, cloth, and etc.