Well, it's really that last one doing them in, along with not being any more competent than their Russian opponents. That last is obvious from their inability to do more than turn this into a stalemate. So, better gear, better tanks, or whatever isn't buying them much. They need better men and training methods that will produce more competent troops.
I remember decades ago while in boot camp, that there were Iranian (pre Ayatollah when the Shah was in power) sailors training on base too. I, we, was / were told they were there for a two-year program to train them to do what we were expected to learn in eight short weeks. That difference shows today in how much less competent the Iranians have proven in wars with Iraq, and operations in the Gulf.