I can’t see custom made machines designed to do one job being outdone by a 3D printer doing that job. I think 3D printers have a niche spot for people who want to print very few of a thing or parts that are no longer available. I can see it being used in space travel and maybe other things space/resources could be limited.
Pretty much this. You can replace "metal 3D printing" with "casting" as that's what it effectively is. Appropriate for some uses and materials, inappropriate for others, and usually requiring at least some finish machining.