It seems to me self-evident that *someone* does
understand how any one of those chips works -
they just didn't tell the rest of us.
Though I agree with most of your points, I think it is only self-evident
that someone *once* understood how any one of those chips works.
It is possible (and likely, once a couple of years have passed), that the
information about how it was done then has vanished, even from the hands of
those who once knew.
Vince