imo, 3D printing is the robotics of the the 21st century. Remember how they were going to do all those everyday labour saving jobs in TV programmes from the 60's 70's 80's? Yet dispite being in manufacturing for decades, they are only now beginning to deal with the complex and the common household tasks, and still generally research "toys". 3D printing will be the same, they will address some niches, but their potential is several decades away. Probably wont ever replace mass manufacture of most products, you'd need too many "ingredients".
its going to be much quicker than you think
unions are almost finished