Iran’s missile program stagnated after Tehrani Moghdam was killed in 2010 (the accident is a cover story).
The Khorrmashahr was a pre-2010 project.
The Keibar Shekan and Fattah-1 are simply specialized glide vehicles slapped on a solid fuel missile.
Despite Shahrud Team working over a decade on larger and more powerful Iranian engines (we can see from the test stand burn scorches via satellite photos) there has not been a major Iranian missile family built since Tehrani died.
So what was that 25B per year going too? Not new cruise missiles. Not new highly capable drones. Not new ballistic missiles. Not new air defenses because the network collapsed the first week. Not new radars.
The only speculation I have is that large parts of Iranian military spending was going to buying and transferring weapons to Hezbollah, Yemen, and propping up Syria all those years and yes corruption and capital inefficiency. The rest was maintaining the military and buying items needed for the existing missile program.
I remember one time the Iranian defense industry showed off no less than 4 different MRAPs designs from various vendors and multiple different humvees. And in the end they went and bought Humvees from Russia and gave Iranian MRAPs to Iraqi militias.