3D printed bike

Also, if you don’t have welds or joints you don’t have stress conentrations which are almost always the point of failure. So once the tech gets a lot better, you may well be able to print a whole frame without any joints. Also given the fact that it could be made from a number of materials (maybe even a mixture of metals and plastics) you could tailor the frame to have properties you want. Such as, stiff front end and a more compliant rear. The options are enormous.

I think you're essentially right, but I feel it's worth pointing out that that welds/ joints are not the only cause of stress concentrations, so what you're saying is incorrect. Also, it is already possible to have a stiff front end and compliant rear. Geometry can vary the stiffness of the component and create stress risers all of its own.