Individuals don't count. Small failures are lost in the hubbub. Big failures are held in check by becoming merely small failures at the next highest level on a hierarchy. But in swarm systems, positive feedback can lead to increasing order. By incrementally extending new structure beyond the bounds of its initial state, a swarm can build its own scaffolding to build further structure.
Spontaneous order helps create more order.
Life begets more life, wealth creates more wealth, information breeds more information, all bursting the original cradle. And with no bounds in sight. They hide countless novel possibilities in the exponential combinations of many interlinked individuals. They don't reckon individuals, so therefore individual variation and imperfection can be allowed. In swarm systems with heritability, individual variation and imperfection will lead to perpetual novelty, or what we call evolution.