Almost a half million people get bumped every year, ten percent of that are "involuntarily bumped" or rather, forced off.
The airlines do this because there is no down side for them. All they have to do is give you company credit. That will ensure that the next time you have to fly you will choose them because you want to use up your "credit". And since the credit only applies to full price fares they might be out only a few dollars or perhaps nothing at all.
Make it cash, they have to give you a voucher for a nice meal if it is under two hours and if it is over four they have to comp you a room at the airport hotel.
The airlines would suddenly discover that bumping people cost and they would stop doing it except in case of emergency.
I think those numbers aren’t right but I do like your ideas about comping people cash and a room for a delay more than x amount of time.