You are talking about a case where one, two or three passengers are asked to leave the aircraft and are in turn offered significant compensation. It is a very different different situation when an airline has to offer compensation to all passengers due to a delay. The cost to the company is not at all the same. That kind of practice does exist. The airlines want to entice those people to leave the aircraft voluntarily, without leading to complaints or similar problems. Those are not really the same circumstances.
On September 14th, 2017. See this statement in context.