A psychologist is treating a client for social anxiety using a highly structured therapy protocol that has been proven effective in numerous large-scale research studies. After several sessions, the psychologist observes that the client, who has a unique personal history and specific cultural values not represented in the original studies, is not making the expected progress. The psychologist decides to modify the standard protocol, incorporating different techniques based on their professional experience and understanding of this specific client's needs. This decision to deviate from the established protocol illustrates a common critique of relying solely on a particular treatment approach. Explain this critique.