Possibly because the original artist have long dead and gone, LOL.
And instead, imo, we'd be hearing some modern jerk-off proclaiming that were made as religious symbols to honour ancient gods and deities, etc, etc.
Which the go to default of 90-99% of most Archaeologists and Anthropologists still these days most unfortunately

No sound. It's a computer-constructed visual made from multiple layered photographs
(if I understand correctly). The technology is explained better in the article.

Sorry meant to be reply to comment by @skado below just above/prior to the one posted by @bobwjr, my apologies for placing in wrong position.
@skado As far as I'm aware there was not much in the way agriculture amongst the majority of indigenous Northern American Indian Nations, a bit with, as far as I know, amongst the Cherokee and the others tribes that were once known as the 5 Civilized Tribes on the east coast but most inland they were still basically hunter-gatherers with a few minor exceptions.
btw, fyi, I am part Cherokee and part Navajo Indian.

@Triphid
Yeah, I don't know much about that particular piece of history/prehistory.
Just going by what the article said:
"All chronological data, therefore, point to human activity in the cave during the Woodland period, and specifically the Middle and Late Woodland periods. This was a time when food production and sedentary residential patterns, which had first developed independently in the region several centuries earlier, began to replace mobile foraging as the primary lifeway.'

@skado the article was great too, and I am glad to know i do not need to call The Geek Squad, thanks.

I think they said these were dated from one to three thousand years ago.

@skado Fairlyrecent then speaking in the terms of human settlement after the REAL exodus of early Home Sapiens from the African continent.

@Triphid

Yes. Already transitioning from hunting/gathering to early agriculture.