That's a goal of some projects, for sure. Already, there are cheapish 3D printers that can print over 90% of their components: often, you need to buy off-the-shelf electronic components to complete it.

> And wouldn’t that destroy the 3D printer industry

Already there are printers on the market where you have a choice of buying a kit and assembling it yourself, or paying more to get it already assembled - or paying less and just getting the electronics (plus a download link for the rest of the parts). Some people are happy enough to assemble their own 3D printer, but if you're just starting our with either 3D printing or electronics, that's a pretty ambitious project. 3D printers can be finicky enough even when assembled by someone who knows what they're doing, let alone by a n00b watching a YouTube video.