Attackers advantage in the iterative fast feedback loop? It’s harder to have a loop to ensure you are defending all possible attacks? I guess the loop is you

Attackers advantage in the iterative fast feedback loop? It’s harder to have a loop to ensure you are defending all possible attacks? I guess the loop is you need to attack yourself and fix. But attackers only need a single opening. Finding all possible attacks and patching them against yourself is inherently more expensive?