At industrial quantities, 3D printing is slow, low-quantity, and imprecise. You can fix one of those axes at the expense of making the others even worse.

As an example, I designed a part with micron-scale tolerances. Some 3D printing firms were able to provide it within a week. Others said they could but messed up the tolerances. Milling it out of metal turned out to be faster and more accurate.

As another example, I have a dream of making a part with 100 nm tolerances. It turns out there is only one supplier of 3D printers which can do this, and they are in Germany. One company in my country have their device, but a production run for them costs tens of thousands of dollars per part due to the slow printing required by the high precision and their high fixed capital costs. As a result, they mostly get hired to make molds for more traditional manufacturing methods.