Which part is Islamic? The high interest rates? What part of IR's economics are Islamic? Seriously, be specific.
I know many people are frustrated with this murderous regime, but to call something Islamic - when in fact it has little to no traces of Islam in it except the discourse/ language used - doesn't get at the root of the problem in our culture. And if we don't learn the root of our problems, then we will repeat the mistakes.
As much as I'm against blaming our problems on this and that, be it the English, the Americans, the Russians or Islam, and as much of a stretch as it may seem to blame IR's economic policies on Islam as you've pointed out, you have to agree that with the regime's Islamic platform, most of those who rise to the top are those with hard core Islamic values or at least those who can pretend they have those values.
So, even though individual economic policies are NOt taken straight out of the pages of the Quran, as I'm sure you're pointing out, the people who decide and influence economic policies re obcessed with the pages of the Quran. In other words, we don't have the best people for these jobs staying in the country, let alone rising to the top to the point where they can decide on or influence policy decisions. And this is not only in economics, but in every other field as well, be it foreign policy, domestic and social policies, sports, etc.
It would be real hard to argue that "Islam" is not hindering Iran's development at this point, even if one makes the argument that it's not really Islam, but a particular interprettion of it that is leading to our demise. It's equally harmful to ignore that fact as it is to blame all our problems on it IMHO.