For a couple of years, that was fact. A couple of legions completely destroyed. Rebellions of Judaeans living on islands throughout the empire. If the Persians had decided to join forces with Bar Kochba, that would have been the end of Rome as an empire.
you are completely correct, Eleutheria
In 68 AD Nero died, there was civil war with Galba, Otho, Vitellius, Vespasian, and the Jews revolted, and destroyed legions.
The beast (imperial Rome) was nearly dead. It was a marvel that it survived.