That assumes that civilizations derive power by encasing their host star in a Dyson sphere, which is not a foregone conclusion; that prediction was based on our

That assumes that civilizations derive power by encasing their host star in a Dyson sphere, which is not a foregone conclusion; that prediction was based on our current understanding if technology. Think of Huygens who imagined that Venusians sailed the seas on ships held together with hempen rope.