According to an article published in the New York Daily News a few months after the "Miracle on the Hudson", when US Airways flight 1549 safely landed (watered?) on the Hudson River to the survival of all 155 souls on board, this incident was only the second ever emergency water landing that did not result in significant injuries and casualties in commercial aviation history.
And yet, the safety briefing at the beginning of every commercial flight adhering to aviation regulations spends more time discussing water landings than nearly any other topic, focussing on how to use life jackets, where to find them, where to inflate and where not to inflate them, how to use the emergency rafts, and so on.
Further, a very large amount of weight on commercial aircraft is devoted to equipment chiefly or entirely present to aid in water landings, with most commercial aircraft today having four or six emergency life rafts, hundreds of life jackets, and even the design of the aircraft itself adhering to minimum float time requirements.
With water landings so rarely attempted and even more rarely successful, why is there so much emphasis put on the current, ineffective methods? In other words, if water landings with current methods and technology generally don't work, why hasn't this changed?