The Marketing Management philosophy that primarily focuses on the selling of existing products is:

Selling concept

The product quality and availability did not ensure the survival and growth of firms because of the large number of sellers selling quality products. This led to greater importance to attracting and persuading customers to buy the product. selling concept is a philosophy that assumes consumers are unlikely to buy products unless they are aggressively promoted to do so. This approach typically works well for industries with products that buyers do not normally think of buying, such as insurance or blood donation. It involves high promotional and sales efforts and a focus on creating sales transactions rather than building long-term customer relationships.