Dynamic Modelling of Sustainable Product-LED Growth in Digital Products: Freemium Conversion, User Retention and Market Saturation

Product-led growth has become an important scaling logic for software-as-a-service, platform and other digitally delivered products, yet acquisition, conversion and retention are often managed as separate performance metrics despite operating as an interdependent system. This study develops a literature-informed dynamic model of sustainable product-led growth in freemium digital products, integrating the remaining addressable market, active free users and paying users. The model draws on recent peer-reviewed evidence on digital product management, freemium conversion, software-as-a-service continuance, churn, network effects, subscription retention, and market saturation. Seven product-growth scenarios and four parameter-sensitivity analyses are simulated over 60 monthly periods. The results show that aggressive acquisition accelerates early growth but also depletes the reachable market more rapidly; strong conversion materially enlarges the paying-user base but cannot compensate indefinitely for high churn; and retention becomes increasingly important as a product matures and the remaining addressable market contracts. Network-assisted growth raises medium-term adoption but mainly changes the timing of growth rather than removing saturation constraints. The study therefore argues that sustainable product-led growth should be managed as a dynamic technology-product system rather than as a collection of isolated funnel metrics. It offers a transparent modelling framework that product owners and digital product managers can adapt for scenario planning, experimentation and lifecycle-sensitive growth decisions.