You don’t understand the aviation industry. Many times crews have to be, at the last minute, shuttled to other locations to complete a crew for a flight that would otherwise face delay or cancellation.
And when that happens, they can offer enough to get a passenger to voluntarily remain. Just like Julian Simon devised more than 30 years ago.
UA would have found plenty of volunteers if they offered more money — cash not vouchers.
Did they look for seats on a “sister” airline heading the same direction? Did they call back to HQ to look for another crew that could come from another station?
Probably not, it looks like they just hit the Easy-Button and grabbed a paying customer and threw him off the plane.
Now going forward, forever, my travel plans will be re-accommodated to avoid UA when I can.