The comment answers to how GPT supposedly produces "new interesting concepts and ideas". The comment you are answering is not supposed or perceived to present anything novel. So both your argument and the comment you reply to are technically correct, neither produces any novel idea; only difference is your reply is out of place.

What exactly is a novel idea? Is there any true “novelty” that just suddenly arises in a human brain without having prerequisite experience / knowledge?

I mean, indeed most "novel ideas" are about making novel connections between existing concepts, and more rarely about creating novel concepts. However, bunching together concepts, even if in a novel way, does not necessarily constitute "novel idea" as the connections have to be in some ways meaningful and interesting, in a certain context. In the previous case, which is actually quite typical of LLMs, a "novel idea" was produced by bunching together certain terms, in a way that it looks syntactically correct and even conceptually solid in a superficial manner. But from a scientific point of view, it is non-sensical and, basically, junk. Bunching together concepts as words does not make a scientific idea or theory. This is a complex process in science, that involves different scales of argumentation, none of which is provided by LLMs. But this is as far as merely manipulating language can get one.

I'm pretty sure space-time expands according to scientific literature, doesn't it ? (this is why I picked this weird concept of a shrinking space-time)