George Orwell (”1984, Animal Farm, Homage to Catalonia”) was a master of predicting the social and political direction of the UK and The West. He was not wrong. His warnings were not pretty but were accurate. Mark Steyn is very good but Orwell was the master.
He went to Spain as a Marxist ideolog and fought against Franco. In Spain he discovered the true nature of Marxism. He came back as a slightly left libertarian, somewhat like Rand Paul but not crazy. If he had lived another 20 years he would have become the likes of Victor David Hansen.
For current analysis of The West none is better than Victor Davis Hansen. His vast intellect can call on centuries of history, warfare, and political beliefs and apply it to what is happening today. It is not pretty.
It could just as easily start in some formerly-developed country, now majority-jihadi, attacking a neighbor state who tried to seal its borders. I'm thinking of Poland or Hungary against all of the rest of Europe. Or India vs. Pakistan 2.0.
Could be some unlikely alliances --- like Russia/China/Poland against Muslim invaders from the south.
Islamic states don't seem to mind warring with other Islamic states, either. Sunni/Shia/Talibans all fighting with each other.
Or it could be Steyn is right --- national borders could cease to be important at all, all violence internal and everywhere.