We review two research papers, one from January 15, 2026 by OpenRouter Inc and a16z (Andreessen Horowitz) and another from April 2025 by Andrey Fradkin (Boston University and MIT IDE) which provide uses of OpenRouter, they analyze the evolving market dynamics and user behaviors within the Large Language Model (LLM) ecosystem, primarily using data from the **OpenRouter marketplace**. The studies document that new AI models see **rapid adoption** upon release, with demand patterns suggesting that models are **horizontally and vertically differentiated** rather than being simple commodities. Researchers found that while some releases **expand the overall market**, others primarily trigger **substitution** within specific model families. Furthermore, the data reveals significant **multi-homing**, where a single application utilizes a diverse mix of models to meet different functional needs. Later analysis introduces the **"Cinderella Glass Slipper"** framework, suggesting that models achieve long-term defensibility by perfectly fitting high-value, previously unsolved workloads. This research also tracks the **rising integration of tool-calling** and reasoning-based architectures, emphasizing that **user retention** is becoming the primary metric of success in a competitive landscape.
Sources:
January 15, 2026
State of AI:
An Empirical 100 Trillion Token Study with OpenRouter
OpenRouter Inc and a16z (Andreessen Horowitz)
https://arxiv.org/pdf/2601.10088
April 2025: Demand for LLMs: Descriptive Evidence on
Substitution, Market Expansion, and Multi-Homing
Andrey Fradkin
https://arxiv.org/pdf/2504.15440
