This is like saying that somebody speaking Chinese is just playing the Chinese Room [1] experiment. The only reason it's less immediately obviously absurd here is because the black box nature of LLMs obfuscates their relatively basic algorithmic functionality and let's people anthropomorphize it into being a brain.
This is not quite accurate. The human lips, throat etc have evolved to be better at producing speech, which indicates that it's not that recent. And that it was a factor in the success of groups who could do it better than others.
It likely started "no later than 150,000 to 200,000 years ago."
sources:
https://en.wikipedia.org/wiki/Origin_of_speech#Evolution_of_...
And (1) that process isn't an autocomplete because it isn't reliably text->text. It could be visual->sound, sound-> action, visual->action or visual->visual or any combination. As well as proactively seeking out new stimulus. Modern LLMs aren't limited to text, they just happen to leverage a large model of the language as their most novel element.
(2) We're not talking about internal or emergent processes, we're talking about intelligence. No human is born intelligent. They go through a pretty similar process to LLMs where a lot of data gets dumped on them and they start responding to it.
And yes humans are born intelligent. Have children and it's the most amazing and beautiful thing watching them begin to create out of nothing. For instance with absolutely zero prompting or external guidance children will begin to engage in intentful make believe play, like starting to share their food with their favorite toy.
But this 'something from nothing' is also essentially required if you think about it. Try to put yourself back in primitive man's shoes some tens of thousands of years ago. You know basically nothing about the world around you, yet in the blink of an eye we've discovered the secrets of the atom, put a man on the Moon, created mathematics from nothing, created all the underlying technology and infrastructure required for us to have our little debate here online, and so much more.
I think, therefore I am. You parrot, therefore you are... ?