Elon has been saying this for years. It’s the whole reason behind Mars. A civilization that stays on one planet is betting everything on one life cycle.
Elon Musk on why no civilization lasts forever:
“You do tend to see the same patterns, similar patterns for civilizations, where they go through a life cycle like an organism.”
“Just like a human: zygote, fetus, baby, toddler, teenager… eventually gets old and dies.”
“The civilizations go through a life cycle. No civilization will last forever.”
The question is where we are in ours.