Only one airline explicitly does not overbook flights on purpose: JetBlue. This leads one to expect that their overbooking rate due to flight cancellations (0.5 out of 10,000 passengers) is approximately the rate you'd see across the industry if what you're saying is true. Instead, Delta and United (for example) bump passengers at 10/10000 and 7.2/10000, respectively.

Your assertion requires that you actually provide evidence to counter these facts. As you have given none, I have to assume you are incorrect.