The title of the article is misleading. He didn't steal it, he cheated the casino out of it. This is an important distinction since in the eyes of the law the casino willingly gave him the money when he cashed out. The casino can catch you cheating and prevent you from cashing out, but once you're out the door you're pretty much free (although I probably wouldn't come back).

In fact the article actually says they've identified the man and banned him from the casino. If they had legal backing I'm sure it would have mentioned the manhunt, and not a "near zero chance of recovering the money."