My coworker is a lot smater than Leland Yee-haw, and has figured out that the best way to make knife blades is by taking old hardened carbide steel files and grinding them down. I check his prototype, and yes, it had a much better edge on it than you could possibly get with a 3D printer. And yes, anything you can make with a 3D printer you can make much better with a full machine shop, provided you know what you're doing.
When I was in college, my dorm mate went down to the local chemical store and bought everything he needed to make pyrotechnics (ok, the mercury for the mercury fulminate he made was stolen from the college chemstry lab). Kids can't do that anymore, because lawmakers can't tell the difference between pyrotechnics and explosives. Every fireworks display uses mortars, with the same name and principle of operation as the mortars used on the battefield. We now strongly discourage all Americans from learning how to make things for themselves, and as a consequence the Chinese are now much better at machining than we are.