Pixar’s chief creative officer Pete Docter recently told the press that he doesn’t “think of Pixar as making children’s programming.” By the look of box office returns…
It's hard to tell if the problem really is solely that the family audience isn't interested to go to the movies anymore, because Elemental's proposition feels thoroughly unexciting to me. Pixar has historically attracted audience with surprising new characters as well rich, well researched settings. Elemental absolutely does not sound like it has any of this.
If Pixar was allowed to refocus its pipeline to darker, more mature stories I'd be up for watching them. I don't know that any animation movies make movies like this except studio Ghibli.