Meh, not buyin' it.
Orson Scott Card pointed out that the power of the Roman Empire was bureaucracy. There's a bit in the Durant where he says something awesome like "the emperors over the following three hundred years were noteworthy only in that there were so many of them, and so many of them were so short-lived." The last emperor you can name, probably, is Nero. He died in 68AD. Roman society, on the other hand, continued through Byzantium until fuckin' 1453. That whole "rise and fall" thing was Gibbon being dramatic; really, Julius Caesar was just the last larger-than-life dude to be declared a god.
We're gonna survive Trump. We got too much entrenched bureaucracy and bureaucrats for the whole thing to come apart at the seams. And really - neither the Democrats nor the Republicans want a repeat of Trump at this point. He's a walking, talking demonstration of why the Executive should be limited.