I was using an absurd example on purpose but let's run with it. Say I do what you say. Hot Dog guy sits on my $10 while he builds the perfect hot dog. At any point I can go to Hot Dog guy and get my money back and give up my place in line. So when the perfect hot dog is created and he gives mine to me, is there still a relationship there? Maybe a casual one as we likely talked and got to know each other during the wait. But when Hot Dog guy has tens of thousands of customers lined up waiting for hot dogs does he "owe" me anything? No. He might let me cut in line (Model S/X R-list anyone?) but he can do that at his discretion. If he comes out with some new topping 3 years down the line he doesn't have to offer me just the new topping. It's reasonable to ask me to buy another hot dog if I want the latest. Ok, this analogy is getting pretty thin
So then what were they doing exactly? Were they investors? Those are people who give money to a company in exchange for equity. The early buyers were not investors. They were customers. That's all they were. They gave a company money in exchange for a product. The fact that they put down a deposit is not novel. It is used in lots of other buyer-seller transactions. If Tesla had gone bankrupt they would have become unsecured creditors.
I can't stop you from hanging onto some romantic notion that the Roadster buyers and Tesla have some kind of special connection. But all it's going to do is cause you heartache and stress and life's too short for that kind of disappointment. I'll let you drive my AWD PXX Model 3 when I get it