There is quite a bit of evidence that your brain is analog, not digital. There is lots of evidence that it is both chemical and electrical in nature And while it is capable of logic, it does not rely strictly on any specific form of logic.
In other words, the only working models we have for "intelligence" are nothing like the silicon binary switches we are attempting to use to replicate it.
Analog can be represented in digital: we can mathematically prove this. It's not at all reasonable to say that AGI cannot be achieved because it doesn't use a certain type of material.
So if the brain is an analog computer, then it seems reasonable to believe that we might be able to someday construct an equivalent analog computer (or a digital equivalent thereof).
You make the assumption that any computer we'd try to use to replicate it will inherently be digital and electronic. If we prove unable to replicate a brain this way, nothing is stopping us from using biochemical systems instead.
Analog computers exists, and we have used bio-mechanical systems for computation... Heck, the first "computers" were humans.
Getting hung up on the current preferred paradigm of computation as the only possible one is one of the biggest flaws of the article.
In other words, the only working models we have for "intelligence" are nothing like the silicon binary switches we are attempting to use to replicate it.