Michael Porter developed the Five Forces model in the 1970s to analyze industry profitability and competitive intensity. The model examines five forces: the threat of new entrants, the power of suppliers and buyers, the threat of substitute products, and the intensity of rivalry among existing competitors. Porter argued that understanding these forces could help determine an industry's weaknesses and identify potential opportunities for competitive advantage. The model helps explain why some industries are more profitable than others and allows companies to assess the attractiveness of an industry.