I don't think folk gives them an edge. I think, like us, they just have a lot of wrestlers and going off olympic medal counts they also produce the best athletes in the world. I mean we are talking about USA but they flopped in the Olympics also for mens freestyle. We flopped too with that ridiculous 3 silvers but not as bad as them.
I think Iran's main problem is winning olympic freestyle golds. We have 3 olympic champs since 2000. 1 of those was due to half his weight class failing the drug test. We are now at back to back olympics with no freestyle gold. That is really, really bad for a country that considers itself a major wrestling country. I don't like Dorostkar either. Guy randomly resigns a year prior to the Olympics then randomly comes back the year after. But it's not all his fault.
As for the coaches, we have weight class coaches, Taghavi is is the coach for the lighter weights for example but yes they work under the federation and head coach. Difference is in the USA they mostly train at their own wrestling clubs with their own coaches for the majority of their preparation whereas in Iran they all train at the national camp almost year round. You can't take that system and put it in Iran because while the national camp is certainly an impressive facility, we only have one of those. They have comparable facilities throughout the country.
As for wearing guys out, not all their guys are like that. We currently have and have in the past had guys like that too. Zare wears guys out. Firouzpour wears guys out and will likely be a world champ this year even though he has a terrible style of wrestling. In contrast their 86 this year struggles to wrestle 6 minutes. I think that is more to do with the individual athlete.