One cause (and effect) of the great stagnation, as emphasized by Peter Thiel and others (including myself), is our inability to imagine a future radically different from the immediate past. We view progress as gentrification and more nice restaurants, not fundamental transformation.
This same lack of imagination makes it difficult to understand the primacy of foreign policy in understanding the world on a day-to-day basis. If you lack imagination, you will tend to assume that the current configurations of countries, alliances, and so on are simply going to last.
But they are not, and they never have. And thus the primacy of foreign policy considerations. But for many people this is difficult to grasp.