[dividedbyzero]

Or civilizations stop growing and never get to a Dyson something stage. You're a hundred billion or so immortal beings that can engineer their very wants and propensities, with a trillion autonomous robot minions, near-inexhaustible amounts of raw materials from asteroids, and more than enough renewable energy to live very happily ever after, why keep growing? Maybe the great filter is just that, a shift in priorities that prevents the others from getting big enough to be easily detectable.