Imagine if everything in the world went open source. Then nobody would be getting paid, everyone would starve because they're giving away there work for free.
Most things in this world are profit oriented products produced as a direct result a capitalism. Open source is an offshoot phenomenon in software arising because software is both easier than other forms of engineering (see thousands of bootcamps) and also easily copyable.
However it should be known that most software developers need to have a job in closed source software in order to pay the bills.
Whenever you see something open source you have to know it's an offshoot phenomenon. These are side projects spawned by intense interest but ultimately still a side project to a person's main line of work which is ultimately profitable. Be surprised that there are 3D printers because it's abnormal. The fact that there are no open source 2D printers arises because there's lack of interest and because there's no profit in open source 2D printers.