These individuals are put under immense pressure to perform flawlessly. Any mistakes are picked up on very quickly and a perceived weakness can cause the wolves to circle in an instant. There is no incentive to come clean about mistakes, and immense pressure to cover-up and hide any weaknesses or errors.
You can't avoid human fallibility. If you expect perfection, all you get is lies and deceit. The only way to truly outperform is to institutionalise openness, continual improvement, and learning from our mistakes.