BillConner wrote on Sep 20^th, 2017 at 12:42pm:

Whatever the motivation for painting on rock's, I suspect at some age it all becomes an historic artifact worth preserving.  Likewise, is there a possibility that someone today could paint rocks for the same reasons and with the same intentions as the first nation people did hundreds of years ago?  Would that be deemed worthy of preservation?

It would indeed be worthy of preservation, however, that's the point - in today's narcissistic age we are so distant from our environment that we simply don't have that kind of relationship with the natural world.  So when we paint on rocks, or for that matter, alter the environment in any way it's mostly about, "look at me," which, in my opinion, is not something that is either worth doing or preserving.