Collapse isn't what you think it is
People think of collapse in terms of a building collapse; a sudden, complete destruction of something.
Societies are much more complicated than buildings. A building either successfully opposes gravity or it doesn’t. Society is composed of uncountable different segments of people and infrastructure. It doesn’t typically collapse all at once; Many disparate segments can struggle in many different ways, and many can be completely decimated without the whole system collapsing all at once.
While the collapse of complex system always includes one or more sudden reductions to the efficacy of the system, such decreases are usually less than total. Complex collapse is not defined by sudden, total failure, but by cascading, permanent decrease in net benefit. Complex collapse is a long-term trend of reduction of metrics of importance.
Complexity = Brittleness
The more complex a system, the more sensitive it becomes to changes.
The more complex a system, the more likely change yields greater net cost, not greater net benefit.
Application
The entire world is more complex today than ever before. The central cause of the exponential increase in complexity is the low cost energy provided by the discovery and use of fossil fuels.
All around you, you see the complexity cycle playing out. We are in the collapse portion of the cycle, and the collapse is well underway.