Those "multiple" orders could be three. Big trucking companies might want to kick the tires, as it were, but they'll need to sell thousands of these things to even recoup the development and tooling costs.
They can barely make thousands of the simple model 3, what makes you think they'll ever be able to deliver on the trucks in enough volume to not lose money on the whole thing? Tesla is bleeding cash at an alarming rate, and they have to either figure out their production problems or they'll end up bankrupt before the planned release date of the truck. Preselling model 3s via a deposit scheme to get cash up front was a clever scheme but the jig is up on that one, so they need to either start delivering on promises or some of those model 3 preorders will be canceled and they'll really be in trouble.