I disagree. I'm fine with overbooking because it makes travel more efficient, both environmentally and financially. However, the airlines should offer whatever it takes to fix overbooked flights. Some of the passengers will be glad to be 4 hours late when they are compensated with, say, 5000$. This will naturally lead to a proper balance of overbooking.

You're going to end up with some level of IDB'd (involuntarily denied boarding) passengers in any world where seats/safety equipment break, equipment changes, crew members get sick and/or time out and airline personnel need to be shuttled to crew another flight that would otherwise be entirely cancelled, or unexpected weather [higher than typical temperatures, unfavorable winds] or airport conditions [runway closures/temporary shortening] preclude a full gross weight takeoff.

As a passenger, I appreciate that my airfares are lower and some airfares have increased flexibility because the airlines have a deep understanding of the turn-up ratio and sell tickets in light of that fact. I appreciate the cases where [probably without my awareness] a flight or cabin crew/member [or maintenance tech and part] has been last-minute flown in to crew/fix a flight that I ended up taking rather than having it be cancelled.

Does it suck to be IDB'd? Sure. Does it happen often? Almost never (around 23 in a million or 1 in 44K embarkations). People in the US are about 5.5 times more likely to be killed in a car crash in a given year than be IDB'd on a given flight.

https://archive.is/YfLWG