Nonsense. LLMs can easily build novel solutions based on my descriptions. Even in languages and with (proprietary) frameworks they have not been trained on, given a tiny bit of example code and the reference docs.

That's not novel, it's still applying techniques it's already seen, just in a different platform. Moreover it has no way of knowing if it's approach is anywhere near idiomatic in that new platform.

I didn't say the platform was the novel aspect. And I'm getting pretty idiomatic code actually, just based on a bit of example code that shows it how. It's rather good at extrapolating.