I’m not sure I agree with your interpretation of the phrasing, but I won’t push it. Let’s say that you are correct, and that offering an additional $500 was not required.
Beating a passenger into unconsciousness and forcibly removing him in an effort to save $500 turns out to have been a poor business decision. I’m just sayin’.
United needed to offer free tickets anywhere in the United States. Start with one. Then add a second ticket. Then add upgrades to that ticket. Then add Hawaii. The reality is that half the plane would take the 2 tickets with a cabin upgrade. That’s a free ticket with your wife. Add first class to it and you will have to beat people off the plane. Another thing they used to do in the old days was to give away first class vouchers, another wildly popular choice.
Whether you have business travelers or not on your flight, whether you have people going home or leaving your home, means you will have different appeal to your offers.
Legally they can bump only for overbooked flights while the passenger is outside the plane.