I think 3D printing will never be popular with those people that are currently in the 35+ age range. However, I think that those ages 20 and younger will be the ones to make 3D printing extremely popular in the future. It's going to be hard to convince 35+'ers to go out and buy a 3D printer, wherease those 20 and under will be exposed to them in school, and work, now and in the future.