Yes I saw the electric car movie but it's not a conspiracy to keep oil money flowing. Economic interests are just another way of saying the way the market works. If you say that economic interests=conspiracy, then it's just saying that you don't like or know how the market works.
Sometimes, existing technology is just so good that it prevents new technology from being profitable. Gasoline is easy to use, easy to transport, and profitable. Veg oil is dirty, hard to get, hard to use, and it's not worth the money savings. The prius came along at just the right time, the GM electric car had all the wrong timing, that's what killed it.