That is true. However, Rome was build around the immorality of invading their neighbors and when they ran out of those, anyone they thought was convenient and profitable to invade and plunder. And for most of their history, it brought them great success. It did backfire towards the end for the western empire (and even for the eastern one even as it survived). However, that same immorality that helped to bring them down was the same one that made them an empire in the first place. There had to be some external factors to their eventual collapse to answer the question of why did that thing that had worked for for so long stop working. There are a lot of competing theories in academia regarding this.

However, regardless of what the actually cause of the invade and plunder doctrine failing was, I would argue that it was just the natural cycle of civilizations. They rise for some reason. They reach their peak. And, eventually, when either internal or usually external factors change, the reason that they were powerful disappears or abates, they become weaker as a result, and either collapse or are invaded by a new civilization who rose for some other reason.

Our civilization on the other hand, seems to have immorality just for the sake of immorality right now. And that immorality is the opposite of what build western society. Discipline, strong family values, law and order, and especially the truth is what our society is built on. Every one of these are now being attacked for some odd reason. It's like someone or something is trying to create an internal collapse on purpose and it is definitely not natural. And one of the key characteristics of this manufactured collapse seems to be an insane level of and unthinkable types of immorality. I almost have to wonder if they haven't pushed people to rock bottom already because where else is there to go. What new abhorrent sin will they invent next?