A simple physics concept, that systems tend to equilibrium. The natural state or outcome. A ball rolls down inside a bowl and oscillation back and forth while friction slows it, until it halts at the bottom, forces in balance.
Why don’t we humans reach equilibrium? We continue to grow, consuming, increasing our numbers. Can’t we choose balance? Pick our population and work only enough to sustain it? Apparently not.
A system out of balance, such as an explosion, changes rapidly during a phase before equilibrium because it is driven out by external forces. This forces act upon humanity to drive the population higher. We will reach equilibrium when the death rate matches the growth rate. This might be an equilibrium rife with poverty and misery. Probably not for all.
Right now, a quiet ologarchic coup is setting the stage for 500 Americans to enjoy pleasant lives while the middle class disappears. But, that’s another story.