As previously noted, I'm skeptical of the full Spengler/Yockey theory of cyclical history and highly specialized High Cultures (e.g., Classical and Western being completely unrelated) - particularly Pessimism and Inevitability (the basic problem with all memes of inevitability: if accepted, they become self-fulfilling and are therefore essentially tautological and unfalsifiable).
However, I do believe that Spengler and Yockey had a point with the very basic premise of cyclical High Cultures. Let's assume that Yockey's interpretation of Spengler's philosophy of history has merit. We then run into a problem. We are clearly in the Winter of the West, terminal decline. What happened to the Fall season of the West, of Empire and Caeserism? What happened to that Authoritarian Empire of the West promised and promoted by Imperium, that golden age that would precede Winter?
Yockey, I believe, miscalculated, perhaps due to an optimism inconsistent with his slavish adherence to Spenglerian Pessimism. Thus, by the time Yockey wrote Imperium, the Age of Empire was already over, and Winter was dawning.
What I am saying is this: the Empire of the West was nothing more or less than the age of European Colonialism, the European overseas colonies in Africa, Asia, and the Americas. That's it. Done, finished, and over with, destroyed by the world wars. Just as the French Revolution and Napoleon mark the dividing line between Culture and Civilization for the West, so do the World Wars and Hitler mark the dividing line between Empire and Winter.
It makes sense, really. The West had long been compromised by petty nationalism and by the Spirit of Money. Therefore, the Empire of the West was a pathetically haphazard series of colonial adventures, for the most part motivated by mercantilism and national rivalries. Built on a house of cards, it all came to a swift and premature end, as that same petty nationalism and defense of commercial interests led to the England-Germany rivalry, two world wars, and the collapse of the West. Poor Yockey, looking forward to an era that had actually recently ended. Dreaming of an Empire of a United West, when the real Empire was the competition of the colonial offices of the nations of Western Europe. Yockey, dreaming of an Age of Authority, when instead money and commercial interests ruled.
Well, it's over. We need to save the Peoples of the West, so these Peoples can begin the process of building a new High Culture on the foundation of the ruins of the West. But to do so, we need to learn the lessons of the past. Any idiots who think that the future can be built on the same petty nationalism which led to our downfall - these are indeed idiots, or perhaps traitors.
But, to summarize: Yockey's expected Empire never took place because, if we accept the cyclical history that his views are based upon, then that Empire had already been actualized in the insipid form of the European overseas colonial system.