Who is this "they" you speak of (who can't see it coming)?
The rulers are doing fine -- they've got armies and secret police and offshore investments so that when things turn to shit they can just jet off into exile like the Shah of Iran.
The ordinary folks don't have the money and they don't have the oil, they stay quiet for now because they don't want to be imprisoned or executed and because the rulers spend a small chunk of their surplus on social security.
In other words, the people with money to invest don't care, and the folks who might care are in no position to take action.
It's not like they would not see it coming. Petrol is eventually going to become too expensive at some point, and they should invest accordingly. But numerous past examples of countries relying on raw resources have shown they usually don't adapt and plan, so I don't have too much hope in their case either.