Earlier quoted context omitted.
The point is that we're trying to duplicate something with the ability of the human brain, and we aren't constrained by size. We can cheat (e.g. 1,000,000 times bigger with 1,000,000 times the power, etc). We're just missing an algorithm or two.
ah yes, it's true we can keep adding on processors and memory until we go beyond what's in the brain (i think currently deep mind has ~ 11 billion neurons to our 100 billion), and indeed so far it's helping, but my point is that it's not at all clear that "more = better". there is more complexity involved than simply scale. the machine could become schizophrenic for exmaple (seriously).
you focus only on single brain, when really we need to look at many trillions brains and experiments with complex reward function(real world): billion years of evolution * billions of various creatures born and died within every year. All this giant sequence of experiments converged to current human brain.
In ML terms: to achieve result similar to human brain we need to run that many hyperparameter optimization trials. Or find some better shortcuts than human brain biological structure.