Hi Neil, fun to see you on HN. I agree with your points and I you summarized it very well as "Ultimately, open source is built on trust".
AI is destroying trust in open source and many other areas and I think this will discourage teams from publishing their source code in the future.
On the other hand, personal connections are becoming even more important, which is unfair to the younger generation and people who don't live near tech hubs.
Today's conception of open source is different from the original anyway. It used to be "we made this thing, here's the code" but now it's turned into some kind of weird parasocial thing more akin to Facebook.