This article illustrates and analyses the causes for the limited adoption of Lean manufacturing concepts in proposals for the redesign and improvement of productive systems in serial production companies. Research was conducted using multiple case studies in six companies that approached the redesign of their productive systems with a Lean perspective using a technique called value stream mapping (VSM). Future scenarios presented by the research team illustrate that the companies were not exploiting the full potential of the concepts and techniques inherent within Lean philosophy. The main reasons include technical, theoretical and training shortcomings faced by the teams responsible for their implementation. Thus, the article attempts to present the key factors necessary to exploit the full potential of Lean concepts.