In my headcanon, the light speed weapon explains why even though we're obviously descended from one of the races in the setting, we don't have spaceships or force powers - once one person got the idea they could use a ship as a suicide nuke, everyone did it, until the only survivors literally had to flee the galaxy and stop using advanced technology.

If one views the entire nine-series arc as the story of the fall of a golden age, the last three are actually fairly appropriate, if badly executed.