Correct. Open Source as an informal concept is how almost all software used to work. It was folk like Bill Gates who saw an opportunity to make money by making

Correct. Open Source as an informal concept is how almost all software used to work. It was folk like Bill Gates who saw an opportunity to make money by making it proprietary. Also, some of the formal concepts are more than 20 years old - e.g. Free Software: the precursors of GPL-style copyleft go back to the mid-late 1980s (GPL v1 was published 29 years ago this month).