How he earns: "Cal AI" estimates and logs calories and nutrition just from a photo of your meal. Launched while he was still a teenager, it has been reported to reach tens of millions of dollars in annualized revenue.
How he does it: He narrowed image-recognition AI to one familiar, easy-to-stick-with use — calorie logging — and scaled it fast on the App Store. A great example of making an existing task one notch easier with AI.
What you can learn: It's not flashy new tech — just using AI to make a "tedious daily chore" easier creates huge demand. Niche fit and how easy it is to keep using matter more than age or résumé.