I happened to be on the inside of some early color-inkjet and color-thermal-wax printer technology, back in the 1980s. At the time it was one of those dancing-bear situations: the impressive part is not how well the bear dances, but that it dances at all. People were amazed by the color prints, of course, but it was because 200 dpi of overly vivid colors that bled quite a bit at the edges was still stunningly different from anything you could get without going to a professional print shop.
Of course, it was obviously never going to cut into the business of those professional print shops, because you needed special paper that was super-expensive and inconvenient to work with, the ink permanence was poor, the wax printers were impossibly expensive (five figures in US dollars, and that was in 1980s dollars!), there were so many obvious inadequacies in the output when you held it up next to a real magazine or a color photo...and we all know what happened in the next few decades.
There might be laws of physics that make it difficult for 3-D printing in metals and/or at high precision to improve hyperbolically, the way 2-D printing did. But there are also a lot of smart and well-financed people looking at the problem, and some of them aren't thinking about thousandths of an inch but about angstroms.