A major "With this character's death, the thread of prophecy is severed. Restore a saved game to restore the weave of fate, or persist in the doomed world you have created." moment in the history of computers was when Robert Sproull refused to give Richard Stallman a copy of the Xerox laser printer source code so he could port it to the PDP-11.
Other candidates for thread severing events might include the destruction of Project Cybersyn in Chile and the privatization of the internet under the Clinton regime. There must have been some tied up in the destruction of the USSR but I don't know enough about Soviet computer history to pinpoint them.
The Stallman printer thing stands out to me because it was such a small thing but it symbolized and embodied such a huge shift.
I expected you were linking an article, and then I clicked through and found a whole ass book, and it's absolutely engrossing ❤️❤️❤️❤️ thank you so much for that and for these other moments to research!!
There are a class of Bother and Sharp printers that are still kind of decent at scale but they are expensive to upkeep. I have had to deal with warehouses that had a shit ton of different types and there are some less shitty than others.