>> When the price drops, they can no longer cover their entire budget and will need to borrow or reduce their spending.
And there is another angle to these numbers. They are the prices based on recent exports of oil. Iran isn't a silly country that requires $300 oil to break even. Their oil exports have dropped in recent years. That drop (sanctions) is a separate factor than oil price. If oil exports a halved, the break-even price doubles. But if oil prices climbed Iran would probably find a way to export more oil, decreasing its break even price to something more reasonable.
And there is another angle to these numbers. They are the prices based on recent exports of oil. Iran isn't a silly country that requires $300 oil to break even. Their oil exports have dropped in recent years. That drop (sanctions) is a separate factor than oil price. If oil exports a halved, the break-even price doubles. But if oil prices climbed Iran would probably find a way to export more oil, decreasing its break even price to something more reasonable.