If you took the average human from birth and gave them only 'the most primitive first principles', the chance that they would have novel insights into medicine is doubtful.
I also disagree with your following statement:
> Right now we're trying to essentially train on the entire corpus of human writing. That is a defacto acknowledgement that the absolute endgame for current tech is simple mimicry
At worst it's complex mimicry! But I would also say that mimicry is part of intelligence in general and part of how humans discover. It's also easy to see that AI can learn things - you can teach an AI a novel language by feeding in a fairly small amount of words and grammar of example text into context.
I also disagree with this statement:
> One fundamental difference is that AGI would not need some absurdly massive data dump to become intelligent
I don't think how something became intelligent should affect whether it is intelligent or not. These are two different questions.