I guess you can treat the human brain as an architecture- one of them can't do everything, but it's a general architecture and you can always make more and train them to do whatever.

An AI that can be copied and trivially trained on any speciality is functionally AGI even if you need an ensemble of 10,000 specialists to cover everything.

There's a lot of evidence that most humans can be raised to have a baseline of understanding and proficiency in most domains. (And anecdotally, many people avoid "difficult" things that they're actually capable of. For example, "bad at learning languages" people will probably still end up learning another language to some degree if stuck where it's the only language spoken.)

Given enough time one human can learn to do anything any other human can do. There is a general capacity for learning, even if someone will only ever transform a specific portion of that capacity into actual activity in their lifetime.

True AGI is as elusive as a true Scotsman.

this is a glib version of exactly what i agree with. a human doesn't do the maximal efficiency with the inputs its given, but has a high number of varied inputs that allow the multi part of multi-modal to really shine. We're not a true general intelligence because we can't respond to problems in space or time that are too big or too small for us, outside of the right frame of reference or outside the right frequency of visible light for us to respond to. Also, the amount of processing power we can respond with is capped as well. So when we say AGI, we mean a computer that responds to the same set of stimuli as we do, with a repsonse somewhere in the region we can respond back to. I don't see why a robot with AGI would care about sunburn if their robot arms don't care about heat, and i don't see that as any less general as if us and a matis shrimp are talking about different frequencies of photons we can see

Yeah it's well known that humans intelligence is not a homogenous whole that is general across all domains. Rather it consists of many specialized parts with hard coded purposes, that are cobbled together with a thin layer of higher thinking on top.