In business, as in anything else, a strategy or a plan is simply a set of words unless it can be carried out in an effective way. Because of this, a strategy will only be able to succeed if it is implemented well.
Let us imagine that a firm creates a beautiful plan for cutting its costs by getting workers to accept more flexible work rules. This plan may look wonderful on paper, but the management will still need to get the workers to buy in to it. If management implements this plan poorly, they can antagonize the workers and the workers will not give the plan their whole-hearted support. In such a case, the plan will fail. This is an example of why a strategy needs to be implemented well.
Plans are necessary, but plans on their own cannot cause success. Instead, plans must be implemented well if they are to succeed.