We would not generate novel knowledge if our only interface with the world was a short text based conversation.
In other words, I don't think that's a fundamental difference between humans and AI; we just haven't given AI any opportunity to build novel knowledge.
Part of that is because it can't really interact with the world yet, in a significant way. Part of it is because nobody has cracked on-line learning.
Actually when you give AI the ability to interact with a world, as in RL, it does build novel knowledge.