Some years ago, a nuclear reactor went critical in the United States. A false reading was being sent to the control room about the water level in the core. In reality, the actual water level was not being recorded, but the instrument panel was simply reading the position of a switch that was stuck in an incorrect position. ISO 9000 actually follows that same logic. By being ISO 9000 certified, it is automatically inferred that product quality meets the standard.
Nothing is further from the truth.
By being ISO 9000 certified, we should assume that the company is certified, and nothing more. If a company gives lousy service, or builds a lousy product, it will continue to do so, because it is inept to start with. ISO 9000 is not going to solve this problem. Likewise, a company that builds, or generates a quality product or service, was more than likely well capable of doing this without the additional burden of an outdated and rigid quality system, which is all that ISO 9000 is or ever will be.