It’s probably just that colonizing the entire galaxy is really hard and no society ever has an economic need to. Populations don’t expand exponentially forever

It’s probably just that colonizing the entire galaxy is really hard and no society ever has an economic need to. Populations don’t expand exponentially forever, the recent explosion is an effect of the industrial revolution, and any species that gets a certain size breaks up into subspecies and starts competing with each other. There could very well be individual dyson swarms out there and we haven’t seen them or haven’t realized that’s what they are. But building them around every star in the galaxy is something I’ll never understand why it’s taken as a given.