1)what is your understanding of a sustainable competitive advantage?
Sustainable competitive advantage allows the maintenance and improvement of the enterprise's competitive position in the market. It is an advantage that enables business to survive against its competition over a long period of time.
Competitive advantage (CA) is a position that a firm occupies in its competitive landscape.[1] Michael Porter posits that a competitive advantage, sustainable or not, exists when a company makes economic rents, that is, their earnings exceed their costs (including cost of capital). That means that normal competitive pressures are not able to drive down the firm's earnings to the point where they cover all costs and just provide minimum sufficient additional return to keep capital invested. Most forms of competitive advantage cannot be sustained for any length of time because the promise of economic rents drives competitors to duplicate the competitive advantage held by any one firm.
A firm possesses a Sustainable Competitive Advantage (SCA) when it has value-creating processes and positions that cannot be duplicated or imitated by other firms that lead to the production of above normal rents. An SCA is different from a competitive advantage (CA) in that it provides a long-term advantage that is not easily replicated. But these above-normal rents can attract new entrants who drive down economic rents. A CA is a position a firm attains that lead to above-normal rents or a superior financial performance. The processes and positions that engender such a position are not necessarily non-duplicable or inimitable.
Analysis of the factors of profitability is the subject of numerous theories of strategy including the five forces model pioneered by Michael Porter ...