Today the Canucks are valued at $1.32 billion and Gretzky's 25% cut would be worth a cool $330 million. While it makes sense that he would have wanted to contend for Stanley Cups, hundreds of millions is worth missing out on a cup or two.
In retrospect, this may have been the largest financial mistake from any NHLer in history. However, Gretzky is still worth $250 million today so he is still doing quite fine for himself.