Looks like the millionaire's heroin habit has finally caught up to him. That, and alcoholism. Having lost all his money to addictions, he now joins the ranks of the vagrant, homeless city-dwellers. After years of battling crime and evil, the dark knight, like any public servant, finally came to realize that even if he had his wish to wipe out all evil to protect the bright faces of the good citizens he served, plenty of those "good citizens" would fill the vacuum and take the place of the evil criminals. Realizing that the people you serve and protect are no different than those you oppose, that the only thing separating evil from good is power and opportunity, such that the only sure way to stop evil is to wipe out the human race in its entirety, is enough to drive any public servant to drink and to seek escape from the taint of his own humanity in the warm and numbing comforts of heroin. In this depiction, we see a gaunt batman who has lost so much weight his mask no longer fits him snugly, and he is stumbling his way to the next whiskey bar. . . . and they lived happily ever after.