If they offered $1000 and an additional seat on the next flight they wouldn’t need to inconvenience anyone, someone would be bound to take the deal. The ordeal that man went through was ridicilous (I think he was a doctor who justifiably needed to get to his practice asap) and this kind of practice needs to be changed.
It seems the incident did lead to a change. DoT rules now prohibit airlines from forcefully removing people after boarding to make room on overbooked flights.
So after boarding their only recourse is to offer increasing compensation until someone gets off.