I agree with your first point, maybe AI will close some of those gaps with future advances, but I think a large part of the damage will have been done by then.
Regarding the memory of reasoning from LLMs, I think the issue is that even if you can solve it in the future, you already have code for which you've lost the artifacts associated with the original generation. Overall I find there's a lot of talks (especially in the mainstream media) about AI "always learning" when they don't actually learn new anything until a new model is released.
> Why does it require 100% accuracy 100% of the time? Humans are not 100% accurate 100% of the time and we seem to trust them with our code.
Correct, but humans writing code don't lead to a Bus Factor of 0, so it's easier to go back, understand what is wrong and address it.
If the other gaps mentioned above are addressed, then I agree that this also partially goes away.
> This assumes your adding documentation, tests, instructions, and other scaffolding along the way, of course.
It's not just about knowledge in someone's brain, just about knowledge persistence.