Employees will always strive to maximize their own welfare, not yours.
Paying employees based on their achievements maximizes their incentive to work but forces employees to take on lots of risk.
Ideally you should compensate employees based on effort, not outcome; but effort is much harder to measure than achievement.
Paying employees based on the performance of a large group creates incentives for workers to free ride on the efforts of others.
Two people, or countries, can benefit from trade even if one is better at everything than the other.