I do yearly and even twice yearly blood tests on all of my pups so that I can pick up on something early. My father in law always said a "pound of prevention is worth a pound of cure"....don't know whose quote that was, but it is so true. Even then, sometimes things just happen.
Blaming is a waste of energy in most cases...we just have to deal with things as they come. Knowing why does not change it. Not saying that we should never find out the whys....just saying the focus needs to be on fixing first rather than expend energy blaming when that energy is better focused elsewhere at that time.