Oh c'mon it ain't as bad as all that. Yeah - it's gonna have all the properties of a casting, or worse properties than a casting if you're sticking with the laser sinter. Which is going to make it jaw-droppingly expensive so let's assume it's a casting. But that means you destructively test one in a hundred or one in fifty and move on. Waste to usable material ratio? If you're casting it, it's got the waste of a casting. If you're sintering it, it's got effectively none - you're fusing powder and the unfused powder goes back in the hopper.

Let's presume we're rollin' HDPE. It's going to cast utterly without drama. Our material costs are entirely related to waste so the less we use the happier we are; we have no dross 'cuz it all goes back in the bin. Let's presume we're rollin' aluminum. Yeah that casting is going to be a bit of a nightmare but we can adjust for that. Either way we're in a much better regime than if we have to 5-axis the bitch or weld it up. Ductile iron? I can heat treat it and shot-peen it. It'll magnaflux like anything else.

Heat sinks on Microsoft Surface Book 2s are laser-sintered 3d-printed aluminum. I know. Crazytown. But they make 'em about 300 at a time in a printing process that takes about 5 hours so... it works.