I agree on a lot of the points. I think a key here is that I don't really think anybody knows what to teach people when they do teach them, and your beginning example shows it extremely clearly. You, having almost zero knowledge of OSX, managed to get things going for someone else who's been using it far longer then you have. It's not that you knew specifically how to fix the problem, it's that you knew the basic idea of what was wrong, an idea of things to look for, and enough critical thinking to figure your way through it. Most people miss that point.
While a wifi problem may be harder to fix then others, in most cases a problem can be solved just by knowing the right info to type into Google and then be able to do a bit of thinking over the results and which seem reasonable to try. Not only that, but a bit of knowledge of some basic symbols (Like, Ex. The various Wifi Symbols, or USB Symbol) and some basic UI knowledge (Like, Ex. Knowing what a bar or panel usually look like, and what a normal OS UI look's like. Text-Boxes, Scroll-bars, Check-boxes Vs. Radio-Buttons, Menus, etc....) go a long way.
I in no way expect everyone to become experts (I wouldn't really expect people to become good enough to reinstall the OS, for example. At that point, you'd want to show someone who knows what they're doing before going further). But, taking some time to teach some basics of more generic concepts, how to go about troubleshooting instead of just learning how to fix some basic problems, and some basics of where to look for various things goes a very long way.