Why did Germany - the nation that had produced the great socialist minds of Marx, Bernstein, Engels, Kautsky and so on see so little success in terms of socialism? You did not - to my knowledge see a massive socialist uprising - like the one present in Russia, nor did you see a gradual implementation of socialist ideals - as in Britain. Although I am aware there was some sort of movement through the SPD to my knowledge this was not terribly successful, especially considering the minds behind it.
Also, just as a followup, why did Germany see so many great socialist thinkers?
I simply chose World war 1 as an arbitrary point in history, to help give an idea of when I am talking about, feel free to dance around it if need be.
German socialism was not less successful in comparison to other European states. In fact, the main German socialist party, the SPD was actually one of the more successful parties in organizing in the teeth of some of the harshest anti-socialist laws on the continent. The SPD's share of the federal Reichstag had steadily grown since 1871 so that by 1912 it was the largest political party in the Reichstag. The SPD's growth in its share of the vote was partly derived by its culling of voters from nearly every other political party within Imperial Germany. Although the Bismarckian state had instituted checks insulating the executive branch from oversight by the Reichstag, the growth of an organized socialist party was more unified and dramatic in Germany than any other European state. French organized socialism was riven by factionalism and the British Labour Party had only begun to make headway in UK politics by 1914. Socialist parties in Russia were either underground or focused on trade unionism or agrarian issues. Few of its contemporaries possessed the drive or unity of the SPD.
This of course begs the question of what exactly constitutes success. For Kautsky and the mainstream opinion in the SPD, revolution was a matter that could not be forced and thus the goal of the SPD became to win elections as part of a general strategy to evolve into socialism as capitalism collapsed under its own contradictions. The SPD began to aggressively chip away at the restrictions on the German electorate and co-opt the various social insurance policies instituted by Bismarck.
Although many of the more revolutionary-orientated Marxists castigated Kautsky and the SPD's strategy as weak and vacillating, it was arguably a more viable strategy. Although revolutionary Marxists like Lenin predicted a massive age of revolutionary upheavals was imminent, the track record for socialist upheaval prior to 1917 was mixed at best. Although the Socialist Revolutionaries tried to portray the Revolution of 1905 as just such an upheaval, in reality the 1905 Revolution was a polyglot event enfolding the many groups and movements alienated from the tsarist state. For example, Bloody Sunday, the spark that lit 1905 was the tsarist repression of a march led by an odd Orthodox priest, Father Gapon, who was leading a group of workers to petition the tsar for alleviating the plight of the working classes. It would take the hothouse conditions of the First World War which combined increased industrialization and various levels of economic for organized Marxist parties to gain enough traction to successfully push for a revolutionary upheaval.
Sources
Anderson, Margaret Lavinia. Practicing Democracy: Elections and Political Culture in Imperial Germany. Princeton, NJ [u.a.]: Princeton Univ. Press, 2000.
Berghahn, Volker R. Imperial Germany, 1871-1914: Economy, Society, Culture, and Politics. Providence: Berghahn Books, 1994.
KoĊakowski, Leszek. Main currents of Marxism: the founders, the golden age, the breakdown. New York: W.W. Norton & Co, 2005.
Sperber, Jonathan. The Kaiser's Voters Electors and Elections in Imperial Germany. Cambridge: Cambridge University Press, 1997.