We can conclude that data presenting Iran's GDP figure as anything higher than 300 billion USD is complete BS. The inconsistency alone completely negates the reliability of said data, 250 billion USD vs 1 trillion USD, coupled with the GDP growth trend, completely unbelievable.
Yup, its faulty exchange rate application essentially.
Soviet GDP was afflicted by this a long while too. Its official exchange rate was often based on delusion (similar to quote below). GOSPLAN insularity would set it (ensuring low trade volume) at X:Y, when in reality the demand/supply pressure (to establish a fair exchange rate with world) was far different....leading to all kind of smuggling and black market stuff past the barter policy for essentials (that bypassed the crap exchange rate that no one else wanted to use).
So the asserted valuation in any other currency (USD or otherwise) means very little....as its not based on the requisite trade flow indicators.
Iran has the insularity (along with North Korea etc) for this to be quite strong phenomenon today. Russia is joining them recently now as well.
Where that stuff is accounted and corrected for (i.e look at things volumetrically trade wise and then extrapolate, rather than just blindly apply a faulty govt asserted X-rate), you essentially have a much reduced GDP estimate...that can then be used for further derived estimates like PPP (total volumetric consumption basis).
With highly insular country economies, these conversations are somewhat meaningless in end as there are not even reference points with world trade indicators.
In 2020 Iran exported around 50 billion USD (for a country rich in oil and gas).
That is part of how WB gets the "actual" exchange rate of rial to USD etc.
Because in 2011 it exported almost 150 billion USD in comparison.
With a third of export level now....(to earn and finance say import + CA level etc)....how can economy have stayed at 2011 level etc?....or even grown? It would need huge expansion of other industries and some evidence of productivity there (i.e providing it to world and competing with world references rather than just "domestic").....we simply do not have it.