I doubt the Iranians are going for high end products such as the equipment the other Gulf States are pursuing. They have one of the world's largest oil reserves and largest natural gas reserves, yet they are spending an extremely small amount in actually improving their overall conventional capability (the only significant improvements seem to be in the area of missiles). Iran is vying more for influence in the region than anything else and influence can't really be achieved by fancy military equipment.
The fact that they are actually making their own military equipment though is still an accomplishment nonetheless.
I looked at the extensive list of domestic Iranian defense industry projects/products, and suspect a major portion of their defense budget is hidden in R&D expenses. In some ways, the Iranians are similiar to the Chinese. After being cut off from Russia (China) and US (Iran), they were forced to develop domestic industry to support and produce spare parts. And if you obtained the ability to build all/most spare parts, it's not far from reverse-engineering the whole thing.
And thus we see Iranian companies like Panha, which was initially contracted to produce replacement parts for US-made helicopters, gaining the ability to rebuild, upgrade, and revere-engineer the AH-1 Cobra (Panha 2091). Then they reverse-engineered the munitions like TOW ATGM (Toophan) too.
The Iranians domestically manufacture everything from planes, UAV's, tanks, missiles, APC, SP artillery, ships, submarines, to an assortment of munitions based on US, Russian, Chinese, and domestic/hybrid designs. Except for a small quantity given to Hezbollah, they don't really export these products at a profit, and domestic (Iranian armed forces) purchases are limited.
I have to think all these projects are quite expensive when combined. The Iranian Defense Industry isn't the most advanced, but it's a lot more self-sufficient than any Arab or Muslim-majority state on the planet, including Pakistan & Turkey.