The way things are going, cheap oil gone and climate change rampant, you'll get the world you describe. Will the remaining handful of small tribes get along? Or will they like Goodall's Apes, kill each other because some decided to leave and do their own thing.

This is interesting piece about judeo-xristianism and how it is hardly alone in religions that oversaw great wars. https://medium.com/@johnbrodixmerrymanjr/gods-problems-cdab66ed5f04