What a person leaves standing is what they will return to on the worst day of their life.
A fallback option runs a person's state long before they ever use it, because the mind quietly scores every available route and softens toward the easy one. That softening sets the emotion, the emotion sets the hand, and a people who left their neighbors' altars intact would never have to decide again; they would simply drift back on the first bad harvest.
God commands demolition instead of distance because a burned image cannot be bargained with later, and the burning is what leaves a person cut off from any other possibility. What this costs is the comfort of a second plan, and that comfort is what has been funding every return.