My view is twofold: (a) interstellar travel is prohibitively difficult and expensive; (b) cosmic-scale engineering is nonsensical to advanced civilizations.
Maybe, although I'd expect von Neumann probes or the like would be affordable for a sufficiently advanced civilization.
cosmic-scale engineering is nonsensical to advanced civilizations
Dyson spheres may be more trouble than they're worth, but I'd think they'd at least turn the matter in their solar system into computronium. Although I suppose if their processors are efficient they wouldn't emit much energy for us to detect.