Why do we not have sports sensor accuracy validations for all sports sensors at the highest accuracy level?

At least three research institutes made a big effort to validate the accuracy of sports sensors: 2. Institute for Intelligent Systems Research and Innovation Deakin University, Australia 3. The MEDITATION RESEARCH INSTITUTE SWITZERLAND (MRIS) to review this topic as objectively as possible. 4. Other reserach institutes with highly accurate devices. But how does Garmin, Polar …