It's not even an oversimplification, it's axiomatic. We have easy and tough times, and we have people who lead us into easy and tough times. If we define those who lead a nation out of tough times as "strong men," they are necessarily a product of the tough times they lived through, and vice versa. Without saying exactly what kind of person a "strong man" or a "weak man" is, the saying says literally nothing.
Yeah well, of course it's a bit like the "no true Scotsman" fallacy, because if strong men fail to create easy times, you can always say that apparently they weren't truly strong, and so on, circular logic ;)
