From what I could tell, it took a long time for the academic tradition of making the source available to work its way into the non-academic world. The academic

From what I could tell, it took a long time for the academic tradition of making the source available to work its way into the non-academic world. The academics were using UNIX and other mainframe/minicomputer systems, but non-academics at home didn't have much access to this stuff unless they got themselves an account somewhere they could access through modem. So everyone else was "raised" in the PC tradition, which came from MS-DOS and the 8-bit micros before it. There, there was a bunch of "shareware" and a bunch of freeware available on BBSes, but the whole idea of passing around source code so everyone could benefit or make modifications just hadn't even come up. I grew up on BBSes and the idea of having source code just never even occurred to me honestly, until I started hearing about it when Linux became popular in the early 90s. The first real open-source stuff (which was really Free software), which pushed it as a philosophy, had to be from RMS and his GNU project, but I never even heard of that until Linux came along, and I think it was mostly confined to the insular academic world before this. When Linux came along, the GNU project finally had a kernel and could be put together into an actual working OS, and at the very same time, the internet was really catching on outside the academic world (this is about 1992 remember), and the WWW was only a couple years away. I'd say it was the perfect trifecta: the already-existing GNU software and tools (glibc, gcc, etc. are really important for having a working OS and building stuff), the Linux kernel, and the new-found accessibility of the internet allowing global communication and collaboration.