Are you sure about that? I would say that Linux is in that position because there are similar alternatives (Windows, OS X) that require less technical knowledge

Are you sure about that? I would say that Linux is in that position because there are similar alternatives (Windows, OS X) that require less technical knowledge for equivalent competency. 3D printers on the other hand have 3 big barriers: 1) they're rather expensive, 2) creating an CAD object ≢ creating a word document and 3) there are not many truly compelling printable objects yet. Relevant: http://youtu.be/rO54gzfite4?t=1m41s http://youtu.be/rO54gzfite4?t=1m41s