It's anything but. Good sales usually are driven by how much they make, and if there's any misalignment between your commission plan and what's good for the company they'll optimize their own revenue in a heart beat. It can be very hard to align your commission plan with what the company actually needs if the business you're into is non-trivial. (Think optimizing the use of existing work capacity, selling high profit products rather than easier to sell low profits ones, keeping sales more or less aligned with the company's capacity to hire staff that can deliver, etc. Selling too much too fast is not always a good thing.)