Chegg vs Duolingo: Same AI, Opposite Endings
In 2023 both Chegg and Duolingo adopted the same OpenAI technology. By 2025 Chegg had collapsed — 6.6 million subscribers, down 14%, an $837 million net loss — while Duolingo boomed to 50.5 million daily active users and 41% revenue growth. The deciding difference: Chegg sold students the answer, so when answers became free it had nothing left to sell; Duolingo made students do the work, and AI only made the practice richer.
The lesson is not that AI ruins or rescues education — it is that the same AI helps or hurts depending on whether it does your thinking or makes you think. A World Bank randomized trial in Nigeria (2025) found a six-week generative-AI tutor produced learning gains of about 0.31 standard deviations — roughly two years of schooling — when it guided students to produce answers themselves.