No, not all knives have non-removable blades. In fact, many knives have blades that are designed to be removable for various purposes, such as maintenance, sharpening, or replacement. The design of a knife's blade attachment can vary depending on the type and intended use of the knife.
For example, folding knives often have blades that can be easily removed for sharpening or cleaning. These blades typically have a mechanism that allows them to be folded into the handle when not in use. Fixed-blade knives, such as hunting or survival knives, may also have removable blades that can be detached for maintenance.
On the other hand, some knives have blades that are permanently attached and cannot be easily removed by the user. These knives are often designed for specific purposes or to provide extra strength and stability. Examples include many kitchen knives, utility knives, or certain types of specialized knives like some tactical or combat knives.
So, it's important to note that while some knives have non-removable blades, there are many others that do have removable blades, depending on the specific type and design of the knife.