Quite the opposite, many of the "barbarians" were becoming more organized, and began to use more disciplined formations at the example of the Romans. Possibly what the poster was referring to was the re-organization of the Roman army? Eventually, the auxilia took prominance over the legions in the Empire, and perhaps this is what he mis-remembered?
It was a steady decline for the most part, with the exceptions of the rules of Diocletion, Julian, and a few others, but was by no means an anarchy. There were quite a few civil wars in this time, but that isn't anarchy. Most of the Empire actually ran business as usual if they were away from the fighting.So overall, I question whether the way you represent the Romans' fate as a steady decline that set in around 200-250 AD and proceeded continuously to the collapse of Western Rome is accurate.