EDIT: Improved politeness.

I think this kind of reverence for the efficacy of the human brain is comical.

The acknowledgement and analysis of the efficacy of the single practical example of general intelligence that we do have does not imply reverence. Efficacy is a relative term. Do we have another example of a universal intelligence to compare to?

Perhaps you mention efficacy in comparison to a hypothetical optimal universal intelligence. We have only AIXI and its variants which are only optimal in terms of maximum intelligence at the limits, but are grossly inferior in terms of practicality and computational efficacy.

There is a route to analyzing the brain's efficacy: it starts with analyzing it as a computational system and comparing it's performance to best known algorithms.

The problem is the brain has a circuit with ~ 10^14-10^15 circuit-elements - about the same amount of storage, and it only cycles at around 100 hz. That is 10^16 to 10^17 net switches/second.

A current desktop GPU has > 10^9 circuit elements and a speed over 10^9 cycles per second. That is > 10^18 net switches/second.

And yet we have no algorithm, running even on a supercomputer, which can beat the best humans in Go. Let alone read a book, pilot a robotic body at human level, write a novel, come up with a funny joke, patent an idea, or even manage a mcdonald's.

For one particular example, take the case of the game Go and compare to potential parallel algorithms that could run on a 100hz computer, that have zero innate starting knowledge of go, and can beat human players by simply learning about go.

Go is one example, but if you go from checkers to chess to go and keep going in that direction, you get into the large exponential search spaces where the brain's learning algorithms appear to be especially efficient.

Human technological civilisation exploded roughly speaking in an evolutionary heartbeat from the time it became capable of doing so

Your assumption seems to be? that civilization and intelligence is somehow coded in our brains.

According to the best current theory I have found - Our brains are basically just upsized ape brains with one new extremely important trick: we became singing apes (a few other species sing), but then got a lucky break when the vocal control circuit for singing actually connected to some general simulation-thought circuit (the task-negative and task-positive paths) - thus allowing us to associate song patterns with visual/audio objects.

Its also important to point out that some song birds appear just on the cusp of this capability, with much smaller brains. Its not really a size issue.

Technology and all that is all a result of language - memetics - culture. Its not some miracle of our brains. They appear to be just large ape brains with perhaps just one new critical trick.

Some whale species have much larger brains and in some sense probably have a higher intrinsic genetic IQ. But this doesn't really matter, because intelligence depends on memetic knowledge.

If einstein had been a feral child raised by wolves, he would have the exact same brain but would be literally mentally retarded on our scale of intelligence.

Genetics can limit intelligence, but it doesn't provide it.

The chance that this capability opened up at just the moment when human intelligence was at even the maximum that DNA encoded ape descended brains could reach is negligible.

In 3 separate lineages - whales, elephants, and humans, the mammalian brain all grew to about the same upper capacity and then petered out (100 to 200 billion neurons). The likely hypothesis is that we are near some asymptotic limit in neural-net brain space: a sweet spot. Increasing size further would have too many negative drawbacks - such as the speed hit due to the slow maximum signal transmission.