This document proposes the "Equity Surplus Theory" or "purple sky model". It summarizes existing models like Porter's competitive strategies and the red/blue ocean models. It argues that focusing on customers' underlying value systems, rather than just value offered, can lead to "uncontested loyalty" where competition is irrelevant. By deeply understanding and targeting specific value systems, firms can avoid "comparative myopia" and create sustained competitive advantage through "equity surplus" derived from uncontested loyalty within the market. Future work is needed to test this conceptual model and extract a complete typology applicable across industries.