Depending on use case, you can dodge the enclosure part by using premade enclosures that come with a machining service to make cutouts for ports etc. Eg Hammond, or Polycase. OOM cheaper at small to moderate runs than injection molding; ie $100 set up fees vice $10k+.

This is notable because the enclosure costs for injection molding can dominate costs otherwise. Eg, getting a PCB manufacturered and assembled from places like JLC is cost effective at any volume. There's no comparable option for injection molding.

This is interesting to me, and the article implicitly touches on it; the parts that seem most important: PCB design and firmware writing, other than the time costs, are dwarfed once you introduce injection molded enclosures. Or if you need certification for an intentional radiator.