And how will people and organizations will be motivated to publish anything in that world? Right. Eventually it will just be old data and AI slop in these "knowledge engines".
Your question supposes that AI is and/or will continue to be incapable of producing new content that is as good or better than humans can.
I don't think this is the case. The consensus among experts in the field is that new AI content is currently on-par with about a college-level student in almost every field, up from around high-school level last year. Like chess, it is expected it won't be long before they are far better than the best human expert in every field.
I wouldn't be surprised if the opposite prejudice develops against human-produced work. That is, if someone publishes so-called "human slop" it will be considered a rude waste of time getting in the way of the far superior AI-generated content.
Further, your question supposes that AI is just regurgitating human-produced work. The existing set of human-produced data is indeed used to bootstrap AI systems, but that doesn't imply it will be needed on an on-going basis. There is clear evidence that AI is able to develop new knowledge, in much the same way as a human can.