There is no rational incentive to work harder than average or get into any leadership role with Overwatch.
If you take a lead role, you get no raise, yet have more to live up to on your performance review. Performance reviews are set to prevent rewarding more than 2-4% of the employees, regardless of individual performance, across the board. Since more than that percentage of the workforce is in a lead position, the lead is doing themselves a disservice by accepting the additional requirements.
If you simply perform your job just as you are asked to do, you will be graded as meeting expectations. Going the extra mile in any capacity, from trying to improve quality to the skills of those around you to sacrificing time with your family, working free overtime, producing more than the next coder, stepping up to a lead position (without the additional pay), or even working through Christmas multiple years in a row (real example) will not be enough to earn you anything better than "meeting expectations", as there will be at least a few handfuls of others who will do this, and only a couple of folks are allowed to exceed expectations.
Also, mistakes are quickly and publicly punished. One does themselves no favors by taking risks, as success gains no rewards and failure is quite publicly, quickly and harshly punished.
