People hate change, people are afraid of new technology , I think part of the reason is this, and this isnt a slam to anyone, but with 3D printing, its not something that everyone may have knowledge on how to do it, it not like say resin casting, which is something anyone can do for the most part, if you want to do your own stuff with 3D printing, there is going to be a very steep learning curve for many.
I am sure that software will come along that will make it more user friendly, but I feel that could one reason why