The costs of the Jihadist are low enough they do not need petro dollars nor or they even dependent upon them now. They have many ways legal and illegal of raising money.
Their concern with us is not oil but that we stand in the way of world conquest by their demented co-religionists.
And it is false that the Saudi government supports terrorism. Don't fall for Michael MOOer's foolishness.
This isn't really the topic of the thread, but it is most certainly true that elements of the Saudi royal family support terrorism. Billions of petrol dollars have been come from Saudi Arabia over the last 25 years supporting Wahabbi schools and mosques worldwide, which are breeding grounds for terror.
Some elements of the Saudi government are very pro-America indeed. But they do not speak with one voice.