Here's where the lack of hard game lore and imagination sets in: in my mind, the "Fleet Commander" is pretty much awakened from a long sleep, and he/she is like, "what the hell is a Spire Starship? Why do we have access to alien technology?"
Well, what's your answer? I know that Chris has some idea of what he had in mind, but he's kept pretty quiet. My guess is partly to allow himself some flexibility in future expansions, partly because he sees an opportunity for player agency.