A possible explanation might be that the guys who actually fired the missile have spent three days trying to avoid blame, and that it's taken that long for the truth t make it's way up the leadership ladder.
I suspect if I was an army grunt who'd fired of a shoulder launched missile only to realise just too late that it was a civilian airliner, I'd be AWOL and in hiding for _way_ longer than three days...
We don’t need to. The point is that these elaborate theories are unnecessary. The government likely knew they were at fault, tried to avoid blame, and eventually fessed up. End of story.
The Iranian military would undoubtedly have known which missile systems would have been deployed in the area as well as the launch and impact characteristics of such systems. It would also be fairly unbelievable if one of the launchers came back two missiles short without any follow up.
While the thought-making process leading up to launch may take time to deceiper, I doubt they had any doubt as to what caused the crash.
Do you doubt there are lies between different layers of governance? And do you also doubt there's heavy cognitive dissonance required already in such theocratic nations?
I suspect if I was an army grunt who'd fired of a shoulder launched missile only to realise just too late that it was a civilian airliner, I'd be AWOL and in hiding for _way_ longer than three days...