I in turn will disagree with you. Babylonia was
always restive, and Assyria's borders were
always under threat. Assyria was built on fighting a campaign every single year and winning every one. The moment they stop winning everyone is going to pile on.
Notice your big list of great kings there? Tiglath-Pileser III, Sargon II, Sennacherib, Esarhaddon, Assurbanipal? Notice something about the regnal dates? With one five-year exception, they reigned consecutively for the last 120 years of the Assyrian Empire. They were all militarily successful kings, sure, but the empire's mere
existence was predicated on every single king being so. The
moment that stopped being true, everything fell apart. We remember Nabopolassar because he was the man on the spot when Assyria's grip slackened momentarily;
he wasn't the first to try. Sure, you can postulate another brilliant successor for Assurbanipal, but that's just putting things off for his lifetime exactly. When
he dies, we're back to square one.
The Assyrian Empire was a tremendously strong thing, but its incredible run of luck in kings in the late 8th-early 7th century just bottled up the explosion. It wasn't bad luck that killed Assyria; it was a lack of stupendously good luck.