While I'm sure it's my own fault for getting the anecdotal facts wrong, so
far I've only heard one person actually address the basic question - which
is why is bonding wire so much larger than grounding wire.
But come on, let's try to stick to the question here and not get bogged down
by the anecdotes!
Let me be clear, I DO NOT MISTRUST OR SUSPECT THE WORK AS BEING SUBSTANDARD
OR NOT TO CODE. I'm sure it's perfectly fine, to code, and more than
adequate for my service. It was performed by a bonded and licenced
electrical company. Please ignore my mistaken eyeballed measurements about
wire sizes, ground rod distances.