Breaking, emergency braking in trucks? Kind of like reverse thrust in airplanes.
Drones are extremely weight sensitive. Adding a heavy thruster would massively eat into the payload.
Trucks are also weight limited by the 80k rule. Brakes are far superior.
The hate and politics obsession of the people you're complaining about on here pales in comparison to the guy doing this presentation. He is doing it 24/7 I'm not even sure he sleeps he is so engaged in it.