The Roman Empire had been sacked on several occasions prior to 476 AD. How come the sacking in 476 AD ended the Roman Empire for good?

The Roman Empire wasn't "sacked" in 476 CE. The city of ROME WAS sacked, in c 390 BCE by Gauls and then twice more in the fifth century, by the Visigoths under Alaric in 410 CE and by the Vandals in 455 CE. From about 407 to 450 CE much of the rest of the western Empire and some of the eastern empire was also plundered and wrecked by invading barbarians.

What happened in 476 was not so much a dire event of such magnitude but the abdication of the last emperor, Romulus Augustulus, and the start of the kingdom of Italy under Odoacer.

I think your fundamental question here is, the Roman Empire had suffered grave setbacks on many occasions prior to the fifth century, so why did it succumb to disasters then? The answer is that by c 400 CE the Roman Empire no longer had its old recuperative powers. Essentially it had been abandoned by its own citizens. They would no longer fight for it. Previously they fought like crazy until Rome won out. In the fifth century however, most citizens no longer cared, which made the Empire especially the western empire, very vulnerable. It had to rely on barbarian soldiers but they proved unreliable and gradually took the empire for themselves.

Rome was full of greedy fat capitalists that have never had the stomach for a fight they had tax havens in Constantinople and moved there look at Greece money has no country fu** you I'm off is the cry as you will soon see

Because there were too many illegal immigrants.

it really didnt