You might find elements of answers to your questions there on what motivated the Germanic campaigns and their abandon in a strategical context ( u/Libertat),the political consequences of the defeat in Rome and why did it not lead to a remobilization ( u/Celebreth).

To quote u/Celebreth : it's all about context. Gaul was already part of the Roman political and economical spheres before its conquest and importantly developed on its own. Gaulish political and economic structures were largely hijacked by Caesar during his conquest, as he could use regional road networks, organized grain storage, using allied peoples as recruitment poll for auxiliaries, etc. For what it's worth, it was indeed super-develloped compared to most of Germania (especially since the more develloped parts of the region entered a strong decline after the Gallic Wars) and the conquest of Gaul was importantly supplied by Gaul itself.

It doesn't mean Romans saw no interest in conquering Germania : : Augustus took years in what was one of the "grand ideas" of his reign in investing fiscal and military resources, already planning the forms provincialization could take, more or less modeled on former Gallia Comata's. But it was certainly a different beast militarily-wise both calling upon Roman resources and logistics much more than Caesar had to, and forcing to create from scratch connections and structures to support a conquest.

Indeed, strategic objectives and conquests aren't just a matter of military victories but also about how to exploit these : Roman generals were perfectly able to defeat Germans in battle as Caesar did, but always had to deal with general hostility, being harassed while on the move, and having to regularly "pacify" the region. Romans managed to keep the upper hand, but even after two decades of campaignings and attempts at provincialization, it was still precarious.

Teutoburg wasn't just "one" defeat : it was the loss of three entire legions that weren't easily replaceable and the sign a great deal of things had to be done from scratch while, in the same time, Romans had to deal with an equally problematic situation in Illyricum. It was a huge political blow reveling this precarious hold Romans had on the region : Augustus counted his losses and gains and pulled the plug on what was a difficult conquest to begin with.

Not everything was lost with Varus' defeat, however : Romans having established links between local elites and themselves, either by subsides, alliances or auxiliary service were a strong basis for keeping political influence beyond the Rhine. Tiberius and Germanicus' campaigns in Germania might not have the effect re-taking the region (neither was it the objective) but led to make a political point and having local rulers and elites (even Marobaud, who had previously fought Romans) entering into a client system as it existed in southern Britain, stabilizing the border (which was after all, one of the objective of the Germanic campaigns) at a fairly limited cost; something that Romans essentially maintained efficiently for centuries.