Quote Originally Posted by General Boreaus Brittanicus
The numbers of germans would have been staggering because the Goths and Huns etc would have been able to beat back the germans with combined force.
Neither the Goths nor the Huns were there at the time to throw the Germans back from a reverse migration compare to historic directions, by the general evidence of archeology. But I am far from an expert in these fields and I could be wrong about it.

And who says Rome can't do it? They did conquer Gaul, by all means. Sure, it was more urbanized and slightly less forested, but the Romans were, you know, quite fast learners in many arts of warfare. It's not like their tactics were static; they could've adapted to forest warfare and then proceeded to genocide half the Germans out to thin out the rebels or something. Caesar did it with the Gallic people.

The thing was that there really wasn't that much of an incentive to expand any more that way at the moment, and the effort would be too much for too little gain when even Hispania wasn't completely pacified yet and the riches of Parthia close by. Besides, Augustus' word was final. He was, after all, to the Roman Empire what Washington is to the USA.

The process of conquering Germany would've differed greatly from, say, conquering Greece. There wasn't an existing level of infrastructure available for the Romans to assume control over. Building it all from scratch isn't cheap. That doesn't mean they couldn't do it if they really, really wanted to.