"Pretty much everything" does include "can't print some things" which is pretty much: they control what you can and can't print. So technically you are right and they are right too, but this conversation path led us back in a circle instead of moving the debate forward.
With the 3D printer you can currently print everything on the 2-D printer you can print everything minus one. (actually there’s probably a whole bunch of currency you can’t print which is maybe hundreds of things ) those are completely different systems of control.
No, you can’t. Printer manufacturers are required to prevent printing certain kinds of images on sophisticated printers. And they also print watermarks unique to your printer on every page.
2D printers are not open source and you can still print pretty much anything