Hey ivan,
if I am supposed to fear that, then I think I like being afraid! 
Awesome illustration! Very clear and intuitive. Add DOF to it (as in focus issue) and it is a HOW TO for image taking.
Actually, I thought of opening a thread about that, since it still seems to be something that many people don’t think about - in the same way as most people focus on the camera body (pun intended) and not the lens.
But just now, I want to discuss the image stabilizer issue a bit more. I did a bit more reading on the matter and it seems to be that IF the theory would apply to all situations in the real world, there should be no problems. However, this is unfortunately not so. One of the main problems, I gather, is the fact that the stabilizer does things in a way and at a time that we cannot predict. That means it might be too slow at times or over-responsive at others, which leads to an exacerbation of the problem instead of the intended amelioration (yes, I googled the last word). So we have the fearsome black box. What bothers me still ist that there is actually nothing to quantify anything, but maybe that is because there are just way too many possible combinations - including body, lens, object, light and also, very important, the photographer!!
A few things that seem to be worth pointing out is that an IS can’t predict the future. That means it can only respond to predictable vibrations (as in hand tremors) or such. It cannot 100% prevent a shake from singular event as, say, pressing the release button. I wasn’t aware of that but it kind of makes sense since even if it is super fast it still needs some time to respond which means there will be some blurr even if it manages to catch it before the shutter closes again. Also, it can happen that a certain vibration hits the natural resonance of the IS system which means that it will build up a wild wobble. The latter is often a problem in UAVs, which isn’t our main point here (I guess).
Long story short: It can help, but it can also make things worse. There is no one right answer…