You're assuming there aren't "new things" latent inside currently existing information. That's definitely false, particulary for math/physics.

But it's worth thinking more about this. What gives humans the ability to discover "new things"? I would say it's due to our interaction with the universe via our senses, and not due to some special powers intrinsic to our brains that LLMs lack. And the thing is, we can feed novel measurements to LLMs (or, eventually, hook them up to camera feeds to "give them senses")

No it isn't false. If it is new it is novel, novel because it is known to some degree and two other abstracted known things prove the third. Just pattern matching connecting dots.

The vast majority of work by mathematicians uses n abstracted known things to prove something that is unproven. In fact, there is a view in philosophy that all math consists only of this.