No one knows exactly how oil is made, so it's a pretty dumb nut who bets the farm on the assumption that we will have oil forever, because it's being produced everyday. Remember that the Earth has been around for about 4 billion years. If it took 4 billion years to produce the oil we've consumed over the last 1-1/2 centuries, then it's going to be a long wait before new supplies become available.
We make assumptions all the time because we have to. We assume the sun will continue to shine and that rain will fall. But how smart would it be for you to waste a lot of money developing expensive alternatives to oil if it turns out that they will not compete with oil extraction?
Oh, I see. You were going to spend MY money.