I once flew on a flight from ORD to ROC where I was the only passenger. It was very, very weird to be in a big empty cabin all by myself. The flight attendant just came and did the safety briefing sitting next to me. I asked her why they didn't just cancel the flight, and she said the plane had to be in ROC for the next morning anyway. This was in the 1990s though. I've never encountered anything like that since.
It is still like that. The airline’s operations all depend on the flight crew being in the right place at the end of the flight, which is a higher priority than getting a passenger there.
Dao was taken to a hospital with non-life-threatening injuries, including a broken nose, loss of two front teeth, sinus injuries, and "a significant concussion"; the injuries required reconstructive surgery, according to Dao's lawyer.
and
"He said, 'I can’t get off the plane. I have to get home. I'm a doctor. I have to get to the hospital in the morning.'" Myers stated that her response was not appropriate: "She said, 'Well, then I'll just have to call the police and have you escorted off the plane.'