Sure, complex shapes can be molded by a small programmable device, but what about machines requiring hundreds of parts, composed of exotic materials, many of which can't be 3d printed and which must be carefully machined and fitted together to close tolerances. Imagine replacing even a simple, easily visualizable and familiar device with a 3DP, like a '64 VW sedan, or a sewing machine, a light bulb or a microphone. Sure, a 3dP can easily make a spacesuit visor, but can it build a replacement filter for the air purifier, or a two way ball valve for the coolant overflow, or a gasket for the O2 tank? Yes, 3dp will definitely be useful on a base or a spacecraft, but only for simple parts made of one non-critical plastic-like material or a very simple alloy. Anything electronic or with integrated circuits or chip processors is out of the question.

You keep on confusing "That's possible" with
"No problem". In space, anything that breaks or is lost can kill a mission and crew. And everything aboard has been carefully designed to precise specifications and probably one-of-kind. What you are talking about is not a 3d printer, but Star Trek Replicator technology based on Enterprise Transporter science.

Everything on a spacecraft or Outland base will be the result of the most advanced technology and industrial manufacturing available on earth. You're not going to be able to replace it with any equipment you can carry along with you.

I hate to be such a Debbie Downer about all this, but we can see how meticulous Nasa and ESA and the Russians are when putting together their hardware, and even then it sometimes doesn't work.

To paraphrase Lord Elrond; "This cannot be made by any craft we here possess".