The problem with things like energy that are almost a necessity for modern life is that some individuals cannot afford it, not that "the economy" taken as a whole cannot.

Let's say 5% of Iran's GDP is spent on energy. Not sure what the number is, but whatever. A big chunk but affordable for the economy as a whole. At the market price, maybe 10% of people cannot afford to consume enough energy to meet the necessities of modern life - cooking, not freezing to death, using transportation. If you don't want these 10% of people to be shut off from modern society, you need to subsidize somehow.