Dockadams -- Thanks for sharing your knowledge and insight of the trucking industry. Hopefully Elon Musk has someone like you on his advisory team. I expect that the technology will progress perhaps at a slower pace until some critical mass is reached and then it could take off in a bigger way. I suppose it really depends on the cost/benefit of fossil fuels versus electric in all driving conditions.
As the technology develops and the highway infrastructure adapts to the increased volume, resources will become more quickly available. For example, if a truck runs out of battery charge on a highway somewhere, instead of a single function tow truck, there may be some multi-purpose built tow trucks that have recharge capability.
Well, after military service, I used that experience as a highway worker-maintainer, and later on in the mid 80's, I got into trucking. I cut my teeth on trucks like the cabover Mack, which attained about 5-6 m.p.g. #2 diesel fuel, and those types of trucks belched heavy black smoke, and they stunk of diesel fuel and exhaust. You almost couldn't stand near one, let alone drive one, which were very uncomfortable and tough to operate.
I happened to notice that Musk's tractor design is of the cabover type, in the old days, those attained inherently poor mileage because of the flat front, in Musk's design, the front is more streamlined.
I think more rigorous testing of a rig like that would be essential to find out what kind of quirks it might have, and time to work out the bugs to make it road ready.
Cost of course is a big factor, Musk claims the semi tractor/s he wishes to mass produce will cost between $150,000 and $200,000, most tractors cost that much already, depending on the drive train chosen for a trucking company application. Most tractors that are used locally have 7 speed transmissions, but road tractors have about twice as many. The Mack cabover I drove over the road years ago had a 9 speed split, or 18 speed total, 2 reverse.
In this youtube video, a driver is demonstrating shifting a 9 speed transmission
I would be interested in Musk's design of the type of transmission adapted to long haulers. It's probably something an every day diesel or heavy duty mechanic has never seen before, which raises other questions about possible breakdowns, who might be qualified to service such a truck?