> Forgings and castings all shrink as well, because metal shrinks substantially when it cools.
Forgings and castings also require post-op machining to bring them into tight tolerances, which isn't something that fits the mental model of a lot of people when it comes to 3d printers.
People who don't own 3d printers. There is plenty of cleanup work on a 3d print of any complexity. I find myself even drilling a fair number of holes in some of my prints because the minimum consistent hole size my printer can generate is a few mm.
Forgings and castings also require post-op machining to bring them into tight tolerances, which isn't something that fits the mental model of a lot of people when it comes to 3d printers.