The article introduces the "Cinderella Glass Slipper" effect, a phenomenon observed in the AI space where certain products achieve high retention rates right from their launch, contrasting sharply with the traditional SaaS model. In the traditional SaaS world, early user retention tends to be low. Founders typically release a Minimum Viable Product (MVP), expecting significant churn as they iterate to improve the offering. However, some AI products are managing to attract a loyal user base immediately, as if they’ve found the perfect solution to a specific problem. The key to this effect is the idea of a "foundational cohort." These users are the first to adopt a product and often find that it meets their needs perfectly. For instance, Google’s Gemini 2.5 Pro, launched in June 2025, saw around 20% of its initial users still active five months later. In contrast, later cohorts showed significant churn, as they approached the model with more casual interest and faced competition from newer models. Similarly, Anthropic’s Claude 4 Sonnet exhibited a retention rate of about 40% among its May 2025 cohort, while later users churned more rapidly. The article warns of cautionary tales where AI models fail to create a unique value proposition, resulting in poor retention rates across all user cohorts. Models that lack a clear advantage, like Gemini 2.0 Flash and Llama 4 Maverick, demonstrate this trend with retention curves that resemble those of generic commodities. The Cinderella effect emphasizes the importance of providing a distinct and compelling solution right from launch to lock in that initial, dedicated user base.