[quote=@LHG100]
I agree with all your points, honestly. The biggest issue really is resource acquisition, definitely.

Y'know, now I'm wondering how exactly you'd defend such an operation, if required. After-all, such a massive structure would be an extremely high value target, both for capturing and defending.

Would you fortify the ringworld itself, or would you use dedicated defensive craft? Probably both, or one or the other, depending on what you're defending against, your tech level, and all sorts of other things.
[/quote]

Well given this is space any attacking force could "attack" such an installation from far outside the defender's field of view. Range becomes a non-issue and you could hurtle stuff at such a structure from the next star-system even, the only factor that would need to be considered is predicting where the target will be when the missile reaches it so you can land a direct hit, running enough calculations and mapping a route through the stars and other gravity sources I'd hazard that should someone know all the required variables you could maybe get away with launching something at such a station from the other-side of the galaxy.

This of course will take a significant amount of time and the route will become so complex with so many stars, blackholes, and other objects getting into the way that the chances of failure ramps up exponentially. But the basic point stands: someone could fly something far outside where they could be seen.

So the best defense might be simply early warning so that defensive installations/space craft could intercept and destroy/re-route/capture a threatening object. But that's considering the attacker hasn't developed teleportation technology and could just zap themselves inside the super-structure and attack it from within. Things can rapidly become incredibly asymmetrical.