That would mostly be limited by tolerances, surface finish and specific alloy used. When you end up with a part that needs a lot of steps and removes a lot of

That would mostly be limited by tolerances, surface finish and specific alloy used. When you end up with a part that needs a lot of steps and removes a lot of material you need a machine that is more complicated, more expensive and with a lower throughput than a machine that simply stamps parts out of a sheet, or shapes them through a mandrill. Casting is a whole other deal, you end up with different properties because the way you cast has different requirements than creating the raw stock. If the part or product you want to make can't match with the results of a cast part (more than just surface finish) you simply can't use casting (until some sort or alloy is found that delivers the required properties). You can obviously use other methods, i.e. metal injection, or sintering, or you could simply make it out of plastic. Or you make multiple simpler parts and interface them together (screws, glue, welds etc). But all of those are fine from the construction perspective, but not fine from the aesthetic perspective, and those are valid requirements as well. The manufacturing method generally is selected during a 'design for manufacture' phase, and that phase only comes after you have already established some parameters on the look, feel, and other properties of the product. If you could just make it out of concrete or a single injected piece of plastic and still meet all the requirements, they would probably do just that (as the process is simpler, cheaper, higher volume etc).