Not quite. Huge mass migrations caused German tribes to overwhelm Western Rome. What's fucking weird is no historians are really looking at what caused Eastern people to migrate Europe, and then caused Northern/Central Europeans to invade Rome, but this is a topic for another thread. Just food for thought.
It's still a matter of scholarly debate, but the most popular & enduring theory about the origin of the Huns (who kickstarted the Migration Period) is that they were originally a Turkic nomadic tribe called the
Xiongnu who established an empire stretching from eastern Kazakhstan to Mongolia & western Manchuria, got their asses kicked by the Han dynasty, and then fled westward to avoid further buckbreaking by both the Chinese and their own former subjects (such as the proto-Mongol Wuhuan). Eventually by the mid-4th century they ended up moving into the Ukrainian steppe, where the Goths actually had a settled kingdom already; then they buckbroke the Ostrogoths, chased the Visigoths into Roman history, and the rest is history. Another branch of the Xiongnu also fled south and established the
Hephthalite or 'White Hun' Empire in modern Afghanistan & the neighboring 'Stans, becoming a pain in the ass for the Sassanid Persians and Gupta Indians for even longer than the 'Black Huns' were for the Roman world.
Also the fall of the Romans had less to do with the barb migrations themselves, and moreso 1) endless civil wars & corruption death spirals and 2) an inability to assimilate said barbs as they had done many other peoples before, not helped by the chaos in 1). The Romans allowed barbarian tribes like the Visigoths to stay together as one unit, basically forming their own ethnic enclave in Roman territory, and to preserve their own power structure (kings, warlords, their own Arian priests for those tribes which did convert to that heretical sect of Christianity, etc.) which obviously prevented them (in fact, actively disincentivized) from assimilating into
Romanitas and accepting Roman rule in the long term as peoples like the Gauls, Britons, Greeks and Syrians already had. Probably a lesson in there that's still applicable for modern America. Worth noting that the Germs who
did assimilate, like Stilicho (a Vandal) or Aetius (probably a Goth, and the guy who beat Attila), actually proved enormously helpful to Rome in its twilight years and had a good chance at saving the Western Empire if they hadn't been killed by, respectively, the conniving Senate and the paranoid, incompetent Emperor Valentinian III.
