I too have had too many supernormal events that make me puzzle over the good that comes to us sometimes. How to explain this isn't for me...
The best I can come up with is that there are many more potential opportunities for "miracles" but the people involved don't follow through.
In this account, Sternberger took the time to listen, first to Marya's (the wife) story, a few weeks before his encounter with Bela (the husband). He felt compelled to get Marya's contact information, thus was prepared when he, once again, listened, this time to Bela. Sternberger not only listened but was willing to follow through, to make the effort to reunite this couple. He put forth effort and used some of his material assets (to pay taxi fare) to send Bela to Marya. What if he hadn't been open enough to strike up a conversation with a fellow Hungarian? What if he hadn't bothered to mentally compare the two stories and act upon his conclusions? This is what I mean by following through; it can make the difference between "serendipity" and missed opportunities.
I wouldn't call it "supernormal" or "a miracle" as much as I would say these things happen because someone actually loves his/her neighbor as he/she loves him/herself. Do unto others...
AB