People will buy a Semi EV - won't be Tesla
I've had to write a number of rather dull papers on competition in trucking, and have had the pleasure of knowing a few people who drove and owned semis for a living.
About 40% of truck sales go to people running one or two vehicles. They buy from a particular supplier almost entirely based on service for their particular area. Most drove Scania if they where picking up the tab and when (with my economist hat on) I asked what would be a substitute, they all responded with some variant of "I'd do something else other than drive a truck".
Unless Tesla can offer something that can beat a Scania (or equivalent, eyeball your local truck park) for loyalty and service, they won't find many people willing to lease them. If they are suited to a hybrid or an EV, then they will wait until Scania brings it one out.
Tesla isn't the only one with the ear of governments. I would have also hope Musk was a good enough engineer to recognise a great piece of pre-existing art and re-use it. Trolley trucks for the future :)