The Mountain Man case study outlines the brand's history, successful sales in the beer market, and challenges posed by changing consumer preferences and competition. To address declining popularity among younger demographics, the company plans to launch a product line extension, Mountain Man Light, while considering the potential risks of cannibalizing its existing brand. Financial projections reveal that while the brand may face challenges with higher levels of cannibalization, there is potential for profitability if cannibalization remains below 5%.