Why was Russia the only major belligerent power to experience a revolution and a successful coup d’etat during the war? Was the collapse of the imperial government in Germany at all similar?
The economic situation was similar in France and Britain as well as Germany, but the United States experienced very little of that, in fact, quite the opposite as the industrial boom of the Merchants of Death was primarily responsible for the economic boom of the 1920s. If there had not been a victory by the Allies, or perhaps only a cease fire where the Germans maintained their territorial gains, such revolts might have been successful in at least France, perhaps Britain as well.
Prior to the collapse of Imperial Germany, the U.S.and France formed a democratic alliance that helped stimulate and galvanize the French for the war effort of 1917 and 1918. In contrast, the military dictatorship of Germany, which set the Kaiser's authority aside, antagonized the populace who withdrew support for the war and began the lead-up to the collapse of the empire.
#5 makes a brilliant point. The aftermath of war created conditions of unrest and poverty in all countries involved. This is something that needs to be factored in to our consideration of Russia's revolution. Clearly, Russia's various tensions were worse than other countries which made the unrest have such dramatic results.
Responding to #5's point, we might also note that the United States did not have the same civil strife, perhaps because its own Civil War (1861-1865) was still such a recent occurrence; at the start of WWI (1914), there were still veterans and civilians alive who had experienced Civil War firsthand.
These posts bring up an excellent but often overlooked point -- during World War I, all of the major European powers experienced the rebellion of their citizenry to various degrees. There were strikes and riots in Britian as the food shortage became severe, for an additional example.
Maybe the reason Russia experienced the greatest convulsions is because it began the war in the poorest conditions relative to her European cousins, and the war stressed an already anemic industry and government to the point of moribundity.
The French Army also experienced a major mutiny that threatened to compromise their ability to fight in the early spring of 1917. Nearly half of their forces along the Western Front were in varying stages of mutiny after a disastrous series of decisions by Robert Nivelle. The mutinies were put down with a combination of more generous leave policies, several dozen (around 40) executions, and hundreds of mutiny leaders sentenced to hard labor. What is important to remember about the Russian Revolution is that it involved two stages- the provisional government, which emerged after the abdication of the tsar, and the Bolshevik Revolution, which overthrew the provisional government.
The Russian Revolution was spurred on by increasingly troublesome economic conditions that resulted from the war. Every country in Europe was experiencing a bit of economic and social upheaval, but the right actors were there to influence the unrest into revolution.
It was a bit similar. After all, both collapses were caused by failure in the war. In both cases, the legitimacy of the imperial governments were tied up with their ability to function well. If they could not do better than they did in the war, it was clear that they were defective.
Also, both collapses were started by mutinies within the armed forces.