Which of the following statements about Porter's competitive forces model is not true? Group of answer choices In a free economy, there are very low barriers to entry in all industries. Porter's model focuses on a firm's general business environment. Porter's competitive forces model is the most widely used model for understanding competitive advantage. The power of customers grows if they can easily switch to a competitor's products and services. The more substitute products and services in an industry, the less a firm can control pricing and the lower the firm's profit margins