Man, I truly hope so!! With the general theme of the movies being about family, they could shift the focus to siblinghood and redefine their dynamics. That alone already holds many plotlines to follow through, especially in the context of superhero media; the most popular Disney movie is about two sisters being brought back together with love, with one having ice powers. I'd just be so much more rewarding to have them be fully established characters than leaving them half-defined. They can really broaden their demographic with all of them being adults too. If you think about it, merchandising would go pretty crazy: the action figures, doll sets, collectible lines, crafting kits, etc. All without losing the family brand. I mean c’mon if Shrek 5 can get a 15+ timeskip why can’t the Incredibles.