... For me, you are describing a contradiction in terms. But let me think it through before your eyes.... I may be wrong.
If we are not understanders, but merely users of things that are supposed to make us more autonomous, then it is still the case that others (organisations/associations of specialists) must have the knowledge that ultimately leads to the many products that are sold en masse to the individual. Here 3D-printers.
Self-determination of the individual does not work without a relevant degree of expertise about the very things that enable me to have this self-determination. But if I am exclusively a user (buyer, consumer), if I understand nothing about cars, telephones, engines, ecological and living systems, etc., but merely use them, I become all the more dependent on them, the less my imagination is sufficient for the real experience I need when I deal with a thing in a practical way (this includes people as well).
Mass products are the end result of a multitude of specialisations, which you only find in such organisations called "companies", where this special knowledge is bundled, right? It is therefore important that people come together in organisations because the individual alone cannot mine, construct, design and produce any modern technology device on his own.
The effort and energy (resource extraction included) that has to be expended on the many devices, machines and transport and distribution routes of the specialist companies so that in the end 3D printers come out of it, which are then also supposed to serve as objects of use for the masses, who on this basis achieve a form of independence from these very companies that enable them to acquire and use the printers in the first place, seems to me like a circular argument.
Where in this chain becomes anyone independent from anyone else?
The way I see it, 3D printing technology is perhaps not better than previous methods for production, but different. For example, if you want to print a metal strand of very hard material and at the same time have the printer use a laser to melt and shape the metal used with pinpoint accuracy, you need a damn good computer program (from where? Open source? What about patents?), you need a hell of a lot of electricity because the process requires a lot more energy than simple computing power, and you still need the raw material in pulverised form for the laser and printer to work.
If you were working in a group of specialised people, trained in both theory and practice, in your local area, and they had expertise in physics, chemistry, engineering, architecture, ecology, philosophy, psychology, education, spirituality etc. (i.e. a whole village), then one 3D printer would probably be a good thing for all of them. What if you tried to work with people who would only be users of this technology?
The programmer alone is just as much an "idiot" as the architect, the philosopher as helpless as a child, if he doesn't belong to a group that brings different knowledge in its diversity.
I conclude from this that we, as modern people, in highly industrialized and computerized societies, are ever more dependent on all other people, whom we don't know, never met, never will meet....
This seems to be a particularly difficult mental challenge, as we simply have to rely on the many specialists without ever establishing a personal relationship or bond with them....
Here the question begins to take on a philosophical, metaphysical, spiritual character.
This was only one aspect of your answer. There may be more, I will refer to, if I find some time and muse.
Society is people. People have always been dependent on society. This is why overlords have been able to parasitize collective production, because society has always been mutually dependent, even before the advent of agriculture.
Society has been egalitarian for the majority of time that humanity has existed. Collective industry has only been practiced for a few millenia. Until collective industry arose, overlords had no ability to parasitize it, because it didn't exist. Egalitarian society isn't novel, or potentially unworkable, because it has been how humanity existed for the majority of the time it has existed.
Something that makes it possible for non-specialists to use specialized devices is automation. Open source, as you point out, enables such software to be used without royalties, and machines manage themselves while still being able to be tweaked by users. I have a 1980 VW pickup with mechanical fuel injection. Electronic fuel injection is able to be tweaked with software, which is much easier than altering the function by adjusting the mechanism.
Regarding circular dependence of specialists, this isn't new, and has been a feature of centralized society since it arose. I have never intended, advocated, nor claimed that human beings can be lone wolves, but rather that society does not need overlords, and in fact suffers from their parasitic losses and self-aggrandizing control. Free people can work together to produce mutual felicity, and for most of the time humanity has existed that has been how society has functioned.
Regarding the lack of personal association with people we depend on, that is the present condition. Dunbar's Number is the amount of people we can have personal relationships with, and is likely the result of Stone Age people being limited in the size of local population by local resources.
Having the means to produce goods and services ourselves does not make us islands incapable of associating with one another, and does not preclude specialization and trade between each other, nor obviates larger cooperative undertakings. If a village 3D printer is possible, then a village full of 3D printers is equally possible because the specialists capable of understanding one 3D printer is capable of understanding each of 3D printers. However, since 3D printers are essentially automating positioning the printhead, it's not particularly different to use myriad materials with 3D printers. What's different is the printheads and environment in which the different materials are usable. There is essentially no difference from room temperature in that environment for many materials, like concrete, PLA, and frosting, while steel, glass, and nylon require higher temperatures, and ice, CO2, and etc., require low temperatures.
Using 3D printers, once the technology matures enough so that they are mostly automated, won't be much different than using indoor plumbing.
I can't see where in your scenario people can exist in greater freedom, since you say that 3D printing technology promotes such. The dependency on centralised supply systems such as energy generation, water supply and mass food production would, in my view, remain even with 3D technology, except perhaps for communities living outside the big cities. For autonomous communities that are off the central grids (which I believe is the prerequisite for more free-spirited living), not only would the autonomous supply of food, energy and water be necessary, but also the integration of children and elderly parents into these communities so that those who, for example, cannot yet or no longer work, remain in their midst. Such communities living and working together in larger numbers requires the ownership of land. This land must be of a certain size to provide the necessary conditions for energy needs and food.
The central systems such as social security, taxation, etc. do not allow exit, and because they do not allow exit, people cannot decide to split into self-sustaining smaller units because their energy tied up in the central systems means they have no capacity to organise themselves locally. They simply lack the time and money as well as the know-how to create a version of freedom. I think the most striking point, moreover, is that they do not even recognise or know how to live in greater freedom and accept that the large systems should and may both provide for them and dictate the rules of coexistence.
I am therefore not sure that we are both talking about the same premises, on the other hand I also think that the intervention of the powers deep into the life of the individual is neither right nor good. How, apart from total reliance on the rulers, with whose decisions a large part of every nation seems to agree, does the consent of the masses to further centralising intentions explain itself?
The communities forming or living outside the central networks would have to be released from their grip, I cannot imagine it any other way.
Hence my scepticism that technology alone makes such a thing difficult to imagine. Psychological and pedagogical considerations are also necessary.
In a country as small as Germany, with limited possibilities to appropriate pieces of land large enough for the many in a community to work together, I see bureaucracy and legal possibilities as the biggest problem.
How do you relate to that?