They are meant as prototyping tools, and some do quite well beyond that.
The trouble is, we can't 3D print PCBs .. not safely anyway. There are quite a few more toxic chemicals to deal with, not to mention the complexities you'd run into trying to make multi-layer boards.
Also I think people forgot plastic still cost money.
That's not how they were being hyped a few years ago. Everyone was talking about machines building themselves and "everything factories" sitting in people's garages.
I just sat there and thought "they finally managed to invent an automated manufacturing process that's even more slow and expensive than machining."
The trouble is, we can't 3D print PCBs .. not safely anyway. There are quite a few more toxic chemicals to deal with, not to mention the complexities you'd run into trying to make multi-layer boards.
Also I think people forgot plastic still cost money.