Any chance of a future where hardware can be customized at the design stage, like 3D printing but taken to an even higher level, even for 1-off builds? So prompt-driven manufacturing? For example, a watch with a USB-C port?

One day that watch could be your only PC. And then some type of eyeglass for a screen. Can also do "terrain overlays" Terminator style. I suppose battery power is the bottleneck so maybe long-distance wireless power delivery is the key (as what Tesla originally created.) So no battery at all.