"Rome" fell because it was a military dictatorship abandoned by Constantine, who moved the whole affair to Byzantium in 330 CE, which proceeded to become the biggest city in Europe, a title it still holds. The "Eastern" Roman Empire persisted for another 1100 years until falling to the Ottomans in 1453.

Western civilization has a muddy perception of the "fall" of the "Roman Empire" because Gibbon was an imprecise and uncaring historian who considered the whole of Byzantium to be "decline" since Constantine was the first Christian emperor and Gibbon had beef with Christianity. But because he was British, at the height of the British Empire, Britons went "Is it me?" and from 1776-1945 painted everything they saw in Gibbon colors.

It turns out the ancient Romans were a lot more intelligent than many people give them credit for. While the general Roman public was largely unaware of the fact that lead is toxic, a number of well-educated Greek and Roman writers were aware of this fact and even knew some of the symptoms of lead poisoning.

Furthermore, lead poisoning does not seem to have been nearly as widespread in ancient Rome as many people today assume that it was. Lead poisoning was a public health problem and it was probably a lot more common back then than it is today. Nonetheless, contrary to what many people today assume, most people in ancient Rome were not suffering from lead poisoning on a daily basis and lead poisoning probably did not play a significant role in the decline of the Roman Empire.

Long has there been incentive for historians to curry favor by saying "look at that cautionary tale, let's not be like that" and by insisting that the Romans were awful because they drank from poison cups, nobody has to learn anything from shit like this.