IIRC Rome was conquered (EDIT: sacked, see replies) at least once during its history as a republic and forced to rebuild. An event like that could just as easily have indicated "the end" for them, but it didn't for whatever reason.

Republican Rome was never conquered. Rome was sacked--which, it is often theorized, created a long-standing cultural fear of the Gauls/Celts that remained largely until Julius Caesar's Gallic conquests/genocides--but the attackers did not stay and did not attempt to replace the governing apparatus.

Roman history, particularly pre-imperial, does show a lot of "why exactly will they not just die?", but some level of resilience in large Mediterranean powers of antiquity was pretty common. (Carthage took two wars and decades to lose the Punic Wars.)

Cheers, that fits better with my memory of what I read. That does somewhat diminish my point.

Rome itself became less important over time, and the later emperors never even went there as they were too busy fighting the many civil wars, traitors, etc. or just being assassinated

This is entirely true of imperial Rome, but less true of the republican Rome. In the context of this particular thread, the conversation was centered on republican Rome and whether a recent civil war was an indicator of the transition to empire. I and my parent were observing that republican Rome had endured multiple existential crises which might suggest a civil war wasn't uniquely noteworthy for the progress to empire, but see my other comments for better answers on why I believe that. (I'm not sure history can be charted with that obvious a causality.)

An interesting aside, the civil war being referenced was actually over a question of Roman citizenship, which used to only apply to people in the city. For quite some time, the (now-)Italian peninsula was under Roman control, but its inhabitants were given a sub-citizen status with much lesser rights. The civil war established that citizenship could be offered to a much wider area.

Right era, but I disagree with the reference to which war. The Social War was absolutely not republican Rome's finest hour, but the "uh oh" seeds were planted 15-20 years earlier with the Marian reforms to the army. The Marian reforms created a standing army rather than a conscript-civilian army, which did then fight in the Social War, but the fuse set by those reforms didn't really blow up until after the Social War when Marius and Sulla started fighting over just who got to have all of the consulships and just who was the bigger, manlier man who got to have all their enemies murdered by the public for gold.

...Ahem.

(It is not a pleasant period of history to read about.)

This is probably a myth, but we do know at some point the Roman’s revolted against their king.

Yes, Rome was very civilized apart from genocide, slavery and the breaking wheels.

As opposed to over 400,000 people living in 'modern slavery' in US even today.