Uhh.
Caligula: AD 12 - 24.
Nero: AD 37 to 68.
Deposition of the last Western Roman Emperor: AD 476.
Considering C to have been a direct result of the moral degeneracy of A and B requires quite a leap.
Anywho, for it's last 150 years the Roman Empire was Christian, complete with homosexuality as a capital crime.
FWIW, the peak of the Roman and Greek civilizations happened to coincide with their periods of greatest acceptance of open homosexuality. Personally, I don't thing A caused B here, either, but it is a fact.
Also, the Eastern Roman Empire lasted another 1000 years, till 1453.
One theory is that the behavior of relatively small numbers of elites (or even an underclass) aren’t nearly as important as the character of the civilization as a whole, which usually means what we call middle classes.
Well, you skipped a few misadventures, such as the year of four emperors (69 AD, hmm, right after Nero), the sale of the Empire (to Pertinax, 191 AD, because Commodus was such a monster and left no clear successor). Elagabalus, about 210 AD, a completely dissolute emperor, followed by mainly military warlords until Diocletian and division of the Empire into at least two major and two minor parts, each ruled by a different man. Then came Constantine, who stabilized the monarchy for a time. But Rome was sacked by Alaric in 410 AD and repeatedly assaulted up to and through 476 AD, which is the date Romulus Augustulus was simply deposed. To date the end of the West with that is to note that a corpse dead for 150 years was finally never going to revive, as I see it.
Fall of the Roman REPUBLIC vs. the Roman EMPIRE.....
Just because the United States Republic has crapped out doesn’t mean the Empire won’t last another 200 years before it goes kablooey...
Of course with Empire comes a totalitarian police state, etc etc.... so yeah a whole lot of fun there...