You describe yourself as a rationalist. Unfortunately, you're as mistaken in that as you are in pretty much everything else.
estimate the performance necessary for replicating all of the cortex, as it has a uniform architecture bollocks...
machine learning is already making steady exponential progress Patently untrue, do you know what the word means?...
what future evidence would cause you to update that to a high"higher", enough with the heavy-handed framing probablility? any evidence of advances in the understanding of the G in AGI (see below)....
an AI 'app' that has true adult human level intelligence - like Samantha from Her Er, you seem to have gotten out of your depth, you offer fallacy in place of logic and fantasy in place of reality. You're either ignorant or careless of the "no true scotsman" fallacy and you reference a model of AI developed by a movie scriptwriter LOL...
Say in 5 years, you experience an AI 'app' that has intelligence - but only that of a 5 year old. I've no idea what you think is to be gained by this orgasm of conjecture but it's certainly not a rationalist's argument, it's unfounded speculation about an as-yet-invisible near-term major breakthrough. And what do you mean: "only that of a five year old"? What towering, empty, casual, blind arrogance. Not a parent, are you? ROFL
...
initially its just simulating infant brains that don't do much, and certainly aren't interesting yet You consider the cognitive plasticity of infants to be uninteresting yet anticipate the development of AGI in ML in just a decade or two? HAHAHAHAHAHA. Please stop, it hurts.
You might want to educate yourself a bit more about the G in AGI, at least do yourself the favour of reading the
commonsense problem page and
Vaughan Pratt's very accessible notes on the commonsense reasoning problems observable in Lenat's CYC.
Frankly, I see only simplistic models of intelligence and media-fuelled infantilism; a modern version of the media's feasting off Mary Shelley's fantastical monster and the simplistic models of physiology that underpinned it.
Cheers
Graham