I'd dispute that - I think they actually timed their policy shift well. Their export control policies were hugely symbolic, a totem of guilt. The Germans genuinely, and to their significant credit, feel the moral weight of their nation's history. Their reluctance was commendable and not token. Overcoming it is a clear moral judgement that many will hear.
Not least Moscow's elite. German relations with Russia were once much better than most of the rest of Europe's - Russia does not view Germany as simple US puppet.
Fair enough, and yes, to have the brakes on this is in principle a good thing but for all the same money Ukraine would have been significantly worse off already because of the slow response. But you are right that this is a feature.
No, "Russian control over a key sector to their economy" is not a plausible analysis, imo. You do not specify, but may I assume you refer to Russia's LNG leverage?
It is not reasonable to seek just-so geostategic facts, or single points of leverage, that explain societies of millions and the policies of their governments.
Understanding something of German politics can elucidate origins of German policy.
"Guilt" is a lazy reduction on my part. It references a sense of special German responsibility to never cause or encourage war, especially in Europe - the zeitgeist of West Germany's post-war generation. A recent DW opinion piece summarizes the received wisdom:
"There are good reasons why Germany has adopted the stance of, on principle, not supplying weapons to war or crisis zones – especially when it concerns a region that, within living memory, has suffered the consequences of a terrible German occupation. The danger of further fueling conflicts if more and more weapons are supplied is not one that can be dismissed out of hand." [0]
Knowing so well the sins of their parents, this generation has sought a path to be proud, little-g germans - replacing nationalism and patriotism with moral vocation. Consider this recollection, from an Austrian born in 1947: https://youtu.be/Qmp--Z8pmTU?t=103.
There is so much more to consider: I haven't escaped lazy shorthand. For instance, the German arms industry is fourth largest in the world. Hypocrisy, monitoring, and debate abound [1]. Analyzing a democratic polity oft feels like a fractal fool's errand.
Certainly, all this is not to say Russia has not influenced Germany's foreign, security, and arms exports policies. The described German sense of responsibility includes a particular sensitivity with regard to criticism of Russia, and an eagerness for economic engagement. Russia sacrificed far more to defeat the Nazis than all other allies combined, and Germans know this well, especially Ossies (not so the rest of the West - often a particular grievance of ordinary Russians).
The LNG vulnerability is doubtless a salient consideration in German policy decisions. But they've conclusively demonstrated the other factors have more weight, and they are willing to pay a price for principle. Indeed, previous to the policy change they were paying a different price - the opprobrium and frustration of allies and America - on the grounds on principle.
> But they've conclusively demonstrated the other factors have more weight
In so many words, you have not, at all.
You admit as much yourself. "The German arms industry is fourth largest in the world." But when it comes to Russia, supposedly they now purport it's because they feel the guilt of the WW2 atrocities, that's the reason behind their actions.
Ok then, turn off the gas imports. "No we absolutely can't do that. But it's not about the gas, we assure you. Ex-Chancellor Schroder being Chairman of the Board of Rosneft is just a funny coincidence."
Not least Moscow's elite. German relations with Russia were once much better than most of the rest of Europe's - Russia does not view Germany as simple US puppet.