Fifty years ago, this might have worked. It doesn’t work with FedEx providing ample competition.
I predict that if UPS ignores them within a year most of their drone and driverless fleet will be out of commission due to acts of sabotage.
I used to live next-door to a Teamster. He was not shy about committing acts of sabotage against anyone he thought was a threat to his livelihood. He would brag that he could get away with it, because “I’m a Teamster!”
Scary part is, it would seem that he did.