Yes, if he really wanted to build trikes instead of scam people he could have.
He had more than enough product interest... at the time. Just like Aptera.
He didn't have to go "all in" on a huge manufacturing facility and so many special tooled components i.e. a proprietary engine before getting things going; Slingshot uses GM sourced engines and, well, just about all other commercially available trikes do. Like Vanderhall
https://vanderhallusa.com/ They are a real, going concern with real, available, affordable product. How did they do it? They weren't big shots with bottomless pockets. P.S. And endless fund-raising and endless excuses for not delivering.
Or Tesla. They had Lotus build their first model to their specifications. Low overhead while learning the ropes and building momentum.
There still is a way but I think now it'll have to wait for higher gas prices and also it might need a new name to help wash away the horrible taste of "Elio".