There are two questions: one whether taking a picture and getting a part to buy would be a desirable workflow for customers - and jeesh, it should be obvious that it would be. The other question is whether the process would work. That's a matter of tech, resolution of cameras and the design of the interface. It's easy to imagine the system displaying multiple options for things like the two nearly identical bolts. As this evolves, the system could even offer the means to distinguish the various options ("count the threads", "take a close-up" etc). And point is something like this could keep improving, both in accuracy and the range of items involved where a hierarchical organization is inherently static.