Employers tend to hire too quickly and fire too slowly.
They permit supervisors to rush through the hiring process with an impatience fed by the need for assistance. Few restraints are placed in their paths.
Once the person gets on board, however, the situation changes. If the employee is a poor fit, the supervisor knows that the freedom of action that existed prior to hire no longer exists. Out of fear of wrongful discharge and discrimination lawsuits, many employers shy away from decisive action. As a result, supervisors play a game of procrastination and denial and their employers encourage them.
The co-workers who have to work alongside a poor performer see management's reluctance as what it is: a sign of weakness. They also regard it as an indirect insult to their own professionalism for the lowest acceptable standard of performance becomes the new standard.
The solution is simple yet difficult. Recruitment and selection have to be improved and coaching and discipline have to be expedited. This can be done, but the willpower to do so must be present. Once it exists, the road opens to a much better workplace. But that fortitude must come from the top and too often willpower's substitute is indifference.