The NPR story was about the recording of that song. Iz showed up at three in the morning at a recording studio that he'd booked over the phone. Nobody there knew him, and were startled by this enormous man who showed up with a battered ukulele. Iz then proceeded to change the lyrics and the music, and the recording that resulted— the first take— ended up sitting on a shelf in the studio for five years. When it finally came off the shelf, it became a huge hit.
The point is that nobody involved in the creation of that song knew what would happen to it. Nobody knew it would be rocketing up the charts in Germany fifteen years later. Nobody knew it would long survive Iz.
The thought here is that we need to take chances. Create without expectation. And to know that anything might happen. Nobody knows what song or what book might succeed, either artistically or commercially. Try. And be good to yourself along the way. We lost Iz at thirty-eight. The whole world will miss him.