At the moment, rapid and massive expansion seems likely with tech only just on the horizon.
Enough AI and robotics for an autonomous factory may be a mirage (such mirages have (metaphorically) happened before), but it seems like it's on the horizon.
Even with relatively mundane growth assumptions, that can go from "species inventing writing" to "Dyson sphere completed, is now sending out seeds to every accessible galaxy" on significantly less than the timescale of light crossing a spiral galaxy's disk.
I think its the fact that if we really wanted to, we could probably make it happen already today. On a scale of a couple hundred million years, its possible we could reach most of our own galaxy, which is a small slice of time in the life span of the Milky Way. So the question remains, why hasn't this already happened, or has it?
Enough AI and robotics for an autonomous factory may be a mirage (such mirages have (metaphorically) happened before), but it seems like it's on the horizon.
Even with relatively mundane growth assumptions, that can go from "species inventing writing" to "Dyson sphere completed, is now sending out seeds to every accessible galaxy" on significantly less than the timescale of light crossing a spiral galaxy's disk.