> but legal uncertainty hung around them for years.
I mean if we're going to split hairs and play this game, SCO claimed ownership to alleged Unix code in Linux which wasn't initially resolved until 2008 or so (and further continued for another decade). That never stopped anybody.
Yes, but not having a copy of the source code for ATT Unix stopped everyone from using BSD or any system based on BSD till 1991. Again, before then BSD was very far from being a complete OS.
So BSD has severe shortcomings as an answer to the question that started this thread, namely, "Can you show examples of impactful open software that predates fsf and stallman?"
I mean if we're going to split hairs and play this game, SCO claimed ownership to alleged Unix code in Linux which wasn't initially resolved until 2008 or so (and further continued for another decade). That never stopped anybody.