I am really impressed with the content of your post. I like the fact that you made it comprehensive enough.

Corrosion is an inevitable parasite that has plagued every aspect where one form of material or the other is involved and we can only hope to find the best way to minimize its impact.

However, I will like to point out that Sacrificial anode is one type of cathodic protection (as you have noted) with impressed current being another. Painting, galvanizing and formation of allow should not be considered as types of cathodic protection. In fact, pure metals have superior corrosion resistance than alloys.

The counterpart of cathodic protection is anodic protection which harnesses the phenomenon of passivity.

I hope you don't mind my contributions. Great Job by the way.