Empires are Bubbles

OK, this isn't so much an innovation as an observation. I was thinking about why some empires crumble dramatically, leaving failed states and cultures in their wake (sometimes leading to the collapse of the founding state/culture), while others sometimes retract calmly and deliberately without destroying the heart of the empire (think the UK.) So, it seems, empires, are sometimes like bubbles. I have no idea if this is an original observation, but I've been thinking about it for several days and it feels like there's something there.