Hi everyone!
Here's something I like to think about:
If we, clever aspies, are here on a forum talking about America's impending downfall as inevitable - we cannot be the only ones who thought about this. We draw our clever paralels to previous empires, such as the Roman, we look at how empires grow and fall.
Don't you all think Americans also thought about this? Russians, the Chinese?
A country like China, as humongous and stable as it is right now, I predict it has the capacity to endure a status quo for quite some time. Through all the instability that has affected the world in the past 50 years, China still stands, Russia still stands, and USA still stands.
In fact, they have all grown in power, and Russia has expanded its borders on two or three occasions (three if you count the 2nd Chechnyan war as a reconquest of lost territory)
They are still eyeing out Abkhazia, Transnistria and more of Ukraine, as well as "theoretical" claims that cover all of Russian Imperial land (this would bring Poland, Balticum, Caucasus, Central-Asia and Finland back under Russian control)
My point is - people live and learn.
The Roman empire was not just taken back, but dismantled completely - not even Italy remained in the end, and in Medieval Europe, the previous frontiers of this empire were completely gone, and not a trace could be recognized:
(culture and such obviously survives, I'm talking about "territorial integrity", the existence of a political entity)
Compare this to Germany in the 1940s, it changes its political identity to an "Empire", and conquers tons of land - then falls apart. Disregarding technicalities and reasons - this is an example of a modern empire, that breaks up: German core regions still make out the country, although it is divided in two, for then to re-unite into the original pre-conquest variant (with a few losses, especially to Poland).
The Japanese empire also suffered similar losses - a collapse of all non-Japanese territory, but the actual island of Japan remaining firmly in Japanese control.
The Ottoman empire - the same story - non-Turk areas fell from their control, but Turkey is today the direct successor of the Ottoman empire, and still covers large non-Turk areas (Armenian and Kurdish) resulting in bloodbaths and ethnic cleansing.
America, Russia, China, may very well never collapse. They might lose some of their non-core areas, IF we compare with historical cases.
If we don't compare with historical cases, they might - just might - have found out how to not collapse so damn easily.
Sometimes I consider the possibility that America will indeed keep outdoing both Russia and China in applicable military power, and become a truly unstoppable force - one that will never crumble or collapse or implode, but just exist, exist and exist, untill humanity is all about enslavement and nothing else.