Rome, by inspection of the size of its circuit-wall, the Wall of Servius Tullius, appears to have held something over 100,000 people even in the Early Republican period -- several times the next biggest town in central Italy. It was always a bruiser, a heavyweight among Italian cities, and Rome threw her weight around for over 240 years until Italy was united under her leadership on the eve of her death-match against Carthage.
Thanks for the comment. My version of the last war with Carthage is prefaced with a detailed discussion of the faults of Livys’ history as you have described, and, many of the inaccuracies are footnoted in the book as the pages leaf over and onward as the war slogs along distracted by augury, superstitions, unnatural events of unknown and feared import. Nevertheless, it is a worthwhile read for someone such as myself, with a limited Classical history background.