With all of the choice on the market one tends to shop for the lowest price. Most of the time this sets the product up for failure as the lowest price isn't always the best product.
A knife is a tool, and as any trades person can attest to you're sometimes only as good as the tools you use. Most cheaper knives on the market are made from low quality steel. Such steel is likely to break under hard use, and with knives being the type of tools that people rely on with their lives a broken knife can cause injury or be the difference between life and death.