I think it's usually true, or maybe I should simply say that it's almost always been true in my experience.
It's easy to miss opportunities when we're satisfied and not looking for them. When we have reason to look again, we see what we missed before. Unfortunately, sometimes the needed opportunity is NOT there. But usually, something will appear, and it can seem like magic, or divine providence, or whatever. But really, I believe it's just what happens when we pay attention.