In archaeology I studied about the pulsating state model. The theory is that powerful empires like the Incas had tipping points in the form of natural or man-made catastrophes which caused them to shrink or diminish. After each dip they would make a short comeback but never as large as its zenith. The flickering (or rather pulsating) flames of these empires grew smaller and smaller till they faded away and were ultimately buried by time.
We’ve seen this with Rome, with Egypt, the Mughals and it probably happened earlier in the Harrappan civilization. But at times it feels like it is happening right before our eyes. I came across this article about St. Louis, MO which shows shrinking urban landscape since the late 19th century. Also great examples are cities like Detroit (or once booming town Flynt, MI), amongst others.
There are undertones of similar pulsating state decay in this awesome presentation called the Tragedy of Suburbia by James Howard Kunstler from the TED series. BTW this is an awesome site. I love it and highly recommend everyone watch a couple of vids. Enjoy!