The ultra-expensive knives have 2 attributes that make them worth the money for professional use: they can cut in a single stroke, while lesser knives require multiple; and they can do it thousands of times. For home use that is rarely of any importance, though it can affect the joy of using the knife. For a professional chef, it can be indispensable. I realized this when chatting to a chef friend of mine, who has one knife just for cutting roast beef, uses it about once a month and it cost just under $1,000. It is used for "silver service" at large events; the waiters line up in front of him, holding a silver tray with a single piece of roast beef, and say a number (how many people at their table). The chef then cuts the beef into that many slices. He does 10 trays per minute this way -- or less than 1 second per slice. The knife is so expensive because it is that sharp, and also has special sides so that the meat does not stick (no suction). Unless you plan to serve 1000 people for dinner, there is no value in owning such a knife at home. An extreme example of how special knives can be, and why there will never be consensus on what is the "best" knife, or if that knife costing 10x or even 100x as much is actually "better".