Yes, I'm speaking about my experience as I remember it - not what was objectively possible for someone with the right resources and knowledge at the time :)

Right, I'm not so much pushing back on you as I am establishing a chronology for CATB. Ordinary people were absolutely belting out (what we would now call) open source software by the time it was written.

(That's not the biggest flaw in the essay, of course. It made predictions, some of which turned out to be comically wrong. The true parts of it weren't new, and the new parts of it weren't true.)