what does drawing on the walls of caves or carving "Mother Goddess" figurines have to do with sustainment (food, shelter)?
It's all relative, of course. Painting on a wall with charcoal requires signifigantly less effort than developing written language.
True. I was thinking in terms of Native Americans - no written language, but definitely time for things like art, dance, oral traditions (passing down stories), etc. Filling in gaps between just getting food and shelter secured.