Yeah, GM and the oil companies did some seriously shady things to kill the streetcars and light rail. GM wasn't interested in selling busses, they wanted to sell cars. They knew the trolleys were way more efficient than busses in terms of both energy and moving people around on time...

It's also instructive to note Rudolph Diesel was found dead under mysterious circumstances when he began pushing peanut oil as the ideal fuel for his engine... he claimed petrochemical fuel oil was too inefficient and dirty.