From what I understand? Saudi Arabia has plenty of money banked; They can survive a decade without the sort of windfall profits they've enjoyed.
"SAMA's net foreign assets totaled $628 billion in November, down from a record high of $737 billion in August 2014,"
The marginal price to produce a barrel of Saudi crude is still the lowest in the world, at just three USD. What's going die out once the equipment is worn out (or require extensive subsidy) are marginal plays in developed countries like Canada, the US, and the North Sea, the Arctic, the deep offshore drilling, tight or heavy oil, tar sands, tar shales, smaller fields without economies of scale, and all forms of biodiesel & ethanol (yes, even the most efficient, Brazilian ethanol).
All the oil-dependent economies are going to suffer and compensate monetarily, by drawing down sovereign wealth or cutting expenditures, but the harder bound is the level at which it makes economic sense to stop drilling. Production prices in the above settings are high enough that they just can't make money at $30/barrel, which is a whole other category of problem than not making enough money to feed the government budget which has ballooned only in the last decade taking advantage of higher prices.
http://knoema.com/vyronoe/cost-of-oil-production-by-country