Not entirely.

This isn't really all that different form what happened with Napolean's Empire, the Assyrian Empire, or the Soviet Empire.

The success that people without moral frameworks have is in their aggression. It allows them unrestrained aggression and deception at all times, and in all cases. This means that they get to seize the initiative most of the time. Thing is, once they hit containment, or peak expansion (natural containment), their collapse becomes inevitable and irreversible until the whole system collapses utterly.

They are very prone to cascade failures, particularly without maintenance.

A strong moral framework (any moral framework) is an excellent mechanism to resisting attrition from Leftist aggression, which is why de-moralization has to come first. When you re-assert that moral framework, it may limit your avenues of approach, but it creates a massive defensive bonus to resisting attacks.

Moreover, if you have a strong moral framework, it can allow you to take the initiative on some issues, rather than being reactionary to the latest leftist fad.

It's really a different way of fighting war, rather than being disadvantaged. The issue is the Leftist ideological narratives are so prevalent that people don't really see that other ways of fighting wars are workable, because they are only looking at it from a Leftist perspective.