Since the dawn of the engineering age the model has been one of proprietary information. Techniques, processes, whole systems have been jealously guarded to ensure that the work done stays the exclusive property of the people who put up the original cash. Wiki says that even the ancient Greeks had a form of patent law, the British caught on in the 1300s and the Venetian state formalised it in the 1400s. With the patent laws something called Intellectual Property was recognised and it could be protected. In the early days such monopoly rights were granted by the aristocracy to the inventors and while protecting the income of the inventor they also inhibited parallel development of the idea,
Venetian Patent Statute.
Of course, the proprietary details of complex systems such as a jet engine are of little use to individuals without lots of resources. But in the modern age there are large numbers of products which need few physical resources, software related systems - they are largely intellectual property running on common hardware.
So what suddenly engendered Open Source and what is it anyway? Open Source seems to have appeared on the first BBS, the now forgotten Bulletin Board Systems that just predated the Internet. Many systems were implemented using the Basic programming language copies that had to be distributed as source code. Anyone could download a copy of the BBS software and setup a similar system. The different operators, sysops, changed the software and shared their changes. The principal of modern Open Source fell into place.
The BBS systems were replaced as the Internet developed. But the Open Source idea persisted and the practice of group development of software widened. Now the tag open source is attached to many things from Cola to guns. The gun bit including the development of 3D printable guns.
With 3D printing and file sharing (see thingiverse) ideas can be swiftly shared, copied to a physical object, tested and developed. Now complex systems such as drones can be put together using entirely open source information. The physical structure can be largely 3D printed with a raw material cost of less than 20 euros. Moreover, the complex software to run the drone's onboard control system is also open source.
These model aircraft parts have been downloaded and printed on a 3D printer.
In medieval Britain most of the resources, the land, was owned by the aristocracy. But there was a little land held to be common where the common man could gather fuel and a little food. These were shared resources for mutual benefit. So maybe Open Source as an ancient precursor, but in this case sharing not land but the even more valuable, knowledge, skills and effort.