“And He made from one every nation of men to live on all the face of the earth, having determined allotted periods and the boundaries of their habitation” - Acts 17:26
God is the Author of nations. He is also the determiner of history and the judge of how long any people group will control any part of the globe called earth that He has created. He establishes one people and removes another. Sometimes the “Why?” of it appears clear, at other times it appears to be a complete mystery.
When cultural sin levels become intolerant to Him, the city, or even whole civilization, can seemingly collapse almost overnight. Sodom and Gomorrah are but one example among multiple other ones. Sometimes He uses climatic or geographical natural disasters, and sometimes He uses warring invasions. Almost without exception, the city or culture in question is already dying of internal division, corruption and moral rot.