Europe’s decline came with its rejection of Christianity. This was cultural, historical, and spiritual suicide. The replacements—secularism, Marxism, paganism—were inadequate. Europe, center of Western civilization, lost purpose and meaning. The culture became a wasteland as birthrates declined—and a different people who believed in something entered. Faith, no matter how twisted, encountered weakness. The script had been flipped, because the scenario mirrored what happened when Christians like Cortez encountered uncertain Aztec Montezuma. The Aztecs were impossibly wealthy—but lacked the will to defend their empire.
The only thing which can save Europe is re-Christianization. Revival. Waking up to its heritage and embracing it.