What's going on now is different. The leaders of Western Civilization are committing the civilization to suicide in the name of diversity. This is deliberate, it is not an accident, it was not expected to "be easy." The elites are subjected to the same principles and ideals, during their Harvard, Yale, Oxford educations.
Centuries ago, the Muslim invasion was abhorred. Now, it is welcomed.
Historically, upper classes do not stay unified.
They are not going to now either.