> we might see another Fall of Rome in our lifetimes.

The Western Roman empire took around 80 years to fall. From 395 to 476.

The Eastern Roman empire lasted for several hundred years more.

It's sometimes thought of as a quick obvious event, but it wasn't, it lasted a lifetime. We may already be in the period of time that future historians will refer to as 'the fall'. It may not be obvious from within what stage we are at, or when thee start was.