Answer:
Spengler, in his work Preussentum und Sozialismus - literally "Prussian-ism and Socialism" - discussed at length why he thought liberalism was a bad fit for the Germans. For starters, he thought that the German liberals were simply ignorant of what liberalism in practice entailed ... because liberalism in Britain in particular depended so heavily on what Spengler characterized as values and cultural reflexes. This meant that that the British (through no fault of their own) described and praised liberalism only in terms of what they themselves were consciously aware of, leaving the Germans believing that only that small piece was sufficient to be good liberals. In Spengler's mind, the predictable result was a cargo cult of English liberty and British parliamentarianism that no German could take seriously.
Spengler believed that the French republican example was no better: an endless clash of egos and passions, tempered only by the historically strong French state - itself a legacy of aristocratic statesmen like Richelieu, Louis XIV, and Napoleon. La Republique was only as effective as its bureaucrats and policemen, which - adding to the confusion - the British example had little need for. In any case, Spengler ruefully argued that the Germans were never more French than when they were engaged in political spectacle, rather than actual politics: again, the Germans' cargo cult version of a foreign idea and its expressions traps intellectuals, politicians, and brawlers alike in the faith that Germany could be remade by a single supreme gesture - a speech, a manifesto, a street fight, etc.
Ironically, Spengler rejected Marxism as something only a bourgeois English gentleman could come up: "the capitalism of the working class" as he called it ... an ethos of competition alien to the true socialist principle as he understood it, which was solidarity. Nobody could make better or more natural socialists than German soldiers.
