All of this assumes there's a benefit to being hostile. I can imagine many quirks of the universe that would moot that point: teraforming is a lot harder & mor

All of this assumes there's a benefit to being hostile. I can imagine many quirks of the universe that would moot that point: teraforming is a lot harder & more necessary than we expect, superluminal travel is impossible, civilizations composed of multiple species outcompete single species, ecological niches are distinct enough that there is little competition, advanced technology renders moot our assumptions about scarcity and inherent competition... When hypothesizing post-seismic shift, the future tends to be orthogonal to our modern expectations as opposed to a simple extension of them. I can see machine intelligences hosted in Dyson spheres chuckling about our space opera sci-fi obsession with capturing planets.