Could I use a 3D printer to print other 3D printers to make money?

Considering that it can print all sorts of metals, plastic and semiconductors in nano precision accuracy, besides many other liquids and nonmetals, Yes! That's a great idea!

You know your getting put on a watchlist now right?

Parts of another one anyway.
Money? Probably not, there's better ways and generally speaking 3D printing a pretty shitty manufacturing process that generally makes fairly shitty materials. There's exceptions but good luck affording those or being able to tool up for them. Even with the exceptions there's now and likely always will be( for the foreseeable future) more limitations.
It's a great tool for what it does but it is what it is and not the miracle manufacturing process that turns your garage into a factory that people with hard-ons on make them out to be. It's a prototyping or hobby process mostly.


(Sorry for the nerdgasm on your tongue in cheek question😞)