This is the place I work at. The data model was designed with a narrow focus. When that turned out to not be viable, the company moved into an adjacent and much larger market. But the names never changed, and the subtle differences between the two worlds was never addressed. So now our application is full of terminology and restrictions that confuse our customers, and our database doesn’t match anyone’s mental model of what the application does. It’s all workable, but IMO we’ve paid (and pay) a not-insignificant price in productivity and complexity because we never took the time to fix these things.

At this point a ground-up rebuild is probably going to be no slower than trying to update the existing app. Neither will be cheap.