I suspect people in that price range go for all solid state instead. The fusion drives are a bit of a compromise in the first place, but the 2tbsp model could be a good budget choice for the right user.
I'm guessing if people need 3 terabytes of storage they already have some sort of DAS or NAS solution. I opted for the 2TB drive for one reason and one reason alone. That model has the 128GB Flash, where as the 1TB model only has 24GB of storage. I didn't need that much storage, but rather I wanted a larger amount of flash storage.