
If you talk Maths (like I am an expert in it, Pheww), the probability of an occurrence of an event can never be zero, therefore there was still a chance that these two people will come across each other some day or the other. But it would take 58 years, that was not expected either.
So you might say that they got lucky, but if it wasn’t for Dave’s undying hope and perseverance and Catey’s hard work it would have not been possible. The point of the whole story is that it does not matter how hard the problems are, all you need is hope and perseverance.