[bigDinosaur]

"Things change" is not the point, rather that empires always have a secular trend of expansion and eventually decline. I was responding to someone who claimed that historical examples don't prove anything, but this trend is as good as proven as one can get in history.

[skybrian]

If they all started at zero and the ones that are no longer in existence end at zero, then roughly speaking, wouldn’t that have to happen?

But in slightly more detail, not every empire has ended, yet, if you count Russia and the Chinese as empires. Also, some empires have had declines that reversed again for a while, such as Byzantine Empire.

[ViscountPenguin]

There are plenty of empires in history that have had growth trajectories far more complex than "rise -> final fall".

Of particular note is China, which made falling and then regaining territorial extent a practical sport.

[kelipso]

By that logic, Europe, Hungary, Austro-Hungarian Empire, Byzantine Empire, Roman Empire, and whatever kingdoms that were there and in all of Europe during and before that are all one empire that kept rising and falling all the time.

[jabl]

The history of China is perhaps not the history of AN empire, but rather a bunch of states/kingdoms, some of which every now and then managed to subjugate their neighbors and build an empire, for a while.