It’s only a threat if you consider the value of design the making of a homologous materialed “thing”.
DIY (and in my opinion the less talked about 3D Scanning) will make a lot of things better, but it is not going to supplant the professional industrial designer who is trained to focus on other things such as research, human factors, market needs, etc.
It’s a huge opportunity from an entrepreneurship standpoint as well IMO. Just think - the entire invisalign process is effectively leveraging this already (scan a 3D model of your teeth, built a transformation in 3D, and create rapid prototyped parts to align them) and they charge thousands and thousands of dollars for the devices alone, not including the doctors fees.