Constant improvement is necessary but not sufficient. Best practices diffuses quickly. Competitors can quickly imitate management techniques, new technologies etc
Strategic position is not sustainable unless there are trade-offs with other positions. Trade-offs occur when activities are incompatible.
Positioning trade-offs are pervasive in competition and essential to strategy. They create the need for choice and purposefully limit what a company offers.
While operational effectiveness is about achieving excellence in individual activities, or functions, strategy is about combining activities.
Strategic fit among many activities is fundamental not only to competitive advantage but also to the sustainability of that advantage. It is harder for a rival to match an array of interlocked activities than it is merely to imitate a particular sales-force approach, match a process technology, or replicate a set of product features. Positions built on systems of activities are far more sustainable than those built on individual activities.