First off, it’s categorically false that no one gets anything done with Agile. Just look at SpaceX. They’ve made NASA irrelevant, and they certainly don’t use waterfall (if you look at the way Elon operates, it is quintessential Agile).

Two, say you’re building a web application with features A, B, C. With waterfall, you only build features A, B, and C. Now it comes the time when users start using the application, and they realize feature C is not needed, but two new features, D and E are required. Waterfall precludes such flexibility and thinks the application is done with Features A, B, and C. But no one in their right mind would that this is “complete.” So I would argue that no one really gets anything done via Waterfall.