I think you're missing the beauty of having a a 3d printer at home and needing an enclosure to do an electronics project and just printing one out, or deciding to print out an ipad stand, fork, screwdriver, guitar, etc.
If 3d printers became widespread, we would have databases full of plans made by people and every 3d print wouldn't be a custom one off
If 3d printers became widespread, we would have databases full of plans made by people and every 3d print wouldn't be a custom one off