With this kind of thing, you can almost completely destroy regulations.
It would be like stomping ants.

As long as there is no central authority or corporation, then the govern-cement would basically have to storm each person's house, break the constitution, and arrest everyone illegally. And that still might not work. (like bitcoin)

I am sure there will be one "ebay" of parts manufacturers. Well, at least one.
Then after that, more people can join.

Creating the environment is tricky. You basically have to get the first 1000 guys all together and all going without taking too long, then other people will start coming in.

The important thing about doing this in your garage is that, if there are no orders, you basically have no overhead. There is no big factory building that is being rented and maintained.