>The future where the world doesn't need their oil
We'll need oil for plastics even if we stop using it for transportation, and Saudi oil is just about the easiest/cheapest to extract, so we'll be using their oil for a long time, but it won't be as grotesquely profitable for them as in the past.
That the whole shooting match right there. "just convenient" is meaningless - we don't make anything unless the cost/benefit works out. If we didn't have oil, it'd be safe to say we'd never have adopted ubiquitous plastic at all.
We'll need oil for plastics even if we stop using it for transportation, and Saudi oil is just about the easiest/cheapest to extract, so we'll be using their oil for a long time, but it won't be as grotesquely profitable for them as in the past.