The legal and procedural hurdles to removing unproductive employees make it nearly impossible to achieve. Even with well-documented and long-standing evidence of shoddy work and low productivity, it has taken us almost 5 years to remove one employee. If you count all the time that management, workforce management, and legal spent working on this case, plus the employee's salary, the cost runs near a half million dollars.
The process of removing unproductive employees needs to be streamlined.
Edit: I would be interested in hearing others' experience with performance management of chronic poor performers, and whether they were able to use the system to terminate their employment.