Unlike the other inventions of 1984, it has taken a while for 3D printing to capture our imaginations and really take off.
I think it had more to do with the fact until 3d printing patents began expiring in 2009 allowing low cost 3d printers to be created and sold you had to spend about $100k or more to buy a 3d printer. I started 3d modeling back in the late 90s and I don't think it would have taken very long for 3d printing to capture my imagination if they were affordable for your average person.