Feeling demotivated is often the most devastating state to be in. Not only do we not operate at our fullest potential, we often make mistakes and regress.
When energy drainers are not taken away, it causes the employee to become paralysed and unable to move. Giving more carrots or applying more punishment/treats (Extrinsic Motivation) does not work. Too often, companies have focused on raising pay or giving in to the employees and the effects of motivation do not last long.
The key is to teach employees to motivate themselves (Motivation Capability) and help them find their personal purpose (Intrinsic Motivation) of helping the company achieve the target.