Running the car on WVO is not easy. You need to make modifications to the car and then you have to make your own fuel. Filtering (and dewatering) are probably critical to success. You also have to operate the car correctly - warming up and purging, specifically. It is not for everyone; in fact it is probably not for very many people at all. But if you enjoy the process, it is quite rewarding. I did not recommend it for most of my friends. That said, without being too dramatic, it was one of the highlights of my life. Perhaps not a major one, but not an insignificant one either. I mostly enjoyed it, learned a great deal and made a few buddies. Even my friends who had no interest in doing it themselves found it pretty fascinating.
Funny thing is my experience was not unique. As I say, it seems the failures were more unique. (Is more unique a thing?) I suspect it may he a case of a house fire being news while a house not on fire isn’t news. If your car runs fine, it’s not a big deal. If the engine blows up, that’s a big deal. It was also a factor that as WVO became scarce, people using it were less inclined to brag about it for fear of losing their supply. As much as some preached the gospel of environmental salvation, there was never enough waste oil to really make any sort of a difference.
There might actually be a book in the study of the whole movement. Besides running cars, trucks and busses on it, people were heating their houses with it, as well as the homemade biodiesel segment. There were a few briefly large companies (large is a relative term) launched and one even sponsored a racing team. I’m not going to write the book, but if someone else does I will enjoy reading it.