In the story "The Happy Prince" by Oscar Wilde, what does the Prince mean when he says " There is no Mystery so great as misery"? 

Could anybody explain this quote to me more clearly, please? This is what I can get from it:  The Prince realized the truth after his death. He lived for a long time in the luxury castle but he knew nothing about the pitiable condition of the poor. It is a mystery that there is so much wealth in the world but the poor still starve and go naked. The seamstress cannot buy her ailing son oranges although she works hard.