a lot of trucking companies disagree with you, including ones which have had hands on with the prototypes, although we dont know you only have to look at analysis of costs of car, and profit margins to realise they are well ahead of the competition on cell price. The next gigafactory, will also include the car manufacturing as well, which will further reduce total cost of car.I watched an engineer's video on the Tesla truck. He initially thought it would be marketing flannel, but did a detailed analysis and found that it would work from a purely engineering angle. Quite well, actually. It's definitely not impossible. However, it is impractical. Partly because of the cost of the batteries and partly because of the size and weight of the batteries - an EV truck will have a much lower carrying capacity than an ICE truck and that adds a lot to the overall cost regardless of the battery price.
You're assuming that Tesla can produce batteries far more cheaply than anyone else. But as you say yourself, you don't know that. Tesla's costs aren't known. It's not really known that they can manufacture batteries any cheaper than anyone else - things that are "well known" aren't known at all. "well known" just means "widely believed". Such things might be true or they might not.
we'll have a much better idea after they release the truck, when we know battery size and profit margin.