I have not read the article to which you refer, but I'd like to point out:
You have never been required to use a special rod as a ground rod. The NEC details pipe, rod, and other made electrodes. There's no reason even a simple piece of #5 rebar can't be used as your electrode.
What the NEC has specified is that rods smaller than the code specified size need to be listed as such. That is, smaller than the 5/8 the code calls for. That's why the galv rod makers passed out those little 'gages.'
Corrosion of ground electrodes has been looked at recently, and there have been plenty of unhappy surprises. It seems that, in very many ordinary situations, the performance and life of the rods and plates is a lot less than was expected. In some reports, the absolute worst results were from ... big surprise here ... rods made of stainless steel. Oops.
