Funny to watch all this talk about the money. Here it is in a nutshell. All pre-orders are liabilities as they are considered deferred revenue. If DP goes out of business, all secured creditors get a shot at remaining assets first, then secondary creditors, a few other entities such as employees pay checks, etc. and at the very end whatever is left might be sent back to people that pre-ordered as a refund. You have no standing and literally no shot at getting anything back if they go out of business. And forget about suing anyone, won't happen because there is no one to get money from since it is a business and liability stops there, it doesn't transfer to the owners since it is a corporation or LLC.
Pre-paid gift cards for retail stores are in the same boat. Years ago, some department store that was in financial trouble actually stated they would cease to honor pre-paid gift cards during their bankruptcy for the same exact reason. Under bankruptcy restructuring, all the creditors had first shot at any assets. All those pre-paid 'deferred revenue' gift cards were a liability to the company that had no secured creditors so they were at the bottom of the list.
Never, ever buy something ahead of time from a startup. Your risk is extremely high compared to any other purchase from an established company.