[Scheherazade]

Yes, the obviousness of the limited capacity of multicultural integration should have been easily deducible to anyone in a position of real power back in the 70s and 80s when the decison was made. Yet, for several decades major countries, having decided to go down the multicultural road, also decided against a sustainable rate of integration over centuries, such as a constant 0.2% annual immigration influx until 2200 CE. The key decision makers instead favoured a destructive course of short term profits within their lifespan, and immense long term costs, that has led to the current outcomes with all the eventual consequences.