You’d have to come up with some way of doing that with machine tools, and in the process of spending all that time, money and difficulty you’d work out why people tend not to do that at any decent volumes! Excepting of course where there are very specific reasons to, such as some of the metal printing done in jet and rocket engines where the geometry would be impossible to do in single parts with casting and machining. But again that’s not exactly low cost, volume manufacture.