If you want a real explanation, this is how defensive wars against an overwhelming opponent are fought. Iran knows that they can't build an iron-clad air defense perimeter, there still isn't a reliable answer against stealth aircraft and cruise missiles. They never had a chance of shooting down every plane that enters their airspace, and that isn't their goal.

Instead, they will fight this war by absorbing blow after blow, hiding their capabilities and striking back when it is advantageous.

All Iran needs to do to win is:

1) Outlast the US air campaign - note this only requires protecting enough of their defensive capabilities to remain difficult. It does not require shooting down every US aircraft that enters their borders. It does not require shooting down most aircraft that enter their borders.

2) Prevent free shipping in the Strait of Hormuz.

That's it. They just need to apply economic pain as domestic and international opposition to the unprovoked attack grows.

I'd argue there is a 3) show other gulf nations that the US can't defend them. They are doing a pretty reasonable job of that right now too considering the infra that is being destroyed daily. The real question is what are their goals and what do they stand to gain? A new list may be:

1) Stay in power. They really were pretty destabilized before this. This war may actually be propping up their government because hitting a bully, despite what the movies say, just gives them more power. Reporting from inside the country is sparse, but it seems like the few stories coming out aren't showing the same level of internal unrest that was there a month ago. This objective seems on track.

2) Increase their influence in the region. This is likely happening by the minute mainly by the fact that the US is losing influence in the region the longer this goes on. The US's loss is Iran's gain. I suspect that actual negotiations are happening in secret between Iran and gulf nations that will have long term consequences. I don't know that this objective is on track, it will take years to see, but if I were betting long term I would bet that Iran in 5-10 years will have much more influence in the region than they had a month ago.

3) Harm the US and Israel. Spain is getting almost hostile and we have a lot of US assets there. Pretty much every country on the planet is turning their back on the US openly. The most 'help' the US has gotten is basing from the UK and, of course, gulf nations supporting strikes. Israel is going to loose military aid for decades and potentially more after this administration leaves. This objective seems on track too.

I honestly don't know how Iran could get a better outcome than what is happening right now. By the end of this they will look rational compared to the US, the rhetoric of the last 50 years will look vindicated giving them increased influence and access in the region and a new generation of extremists will have been created. This has the makings of becoming one of the worst blunders in military history.

I guess it's possible that Russia and/or China delivered some hardware to the Iranians. Doesn't seem far fetched given the low international support for this "excursion". Both countries benefit from a US quagmire.

Air defense is not static. Even fixed launchers can be moved, and reacting to how your enemy is operating is an important part of air defense tactics. The famous F-117 shootdown happened because the air defense operators carefully planned around how the US was using its aircraft. If most Iranian air defenses were destroyed in the first few days, it'd make more sense for them to hold whatever was still available for the sort of situation where they had much higher chances of scoring a kill than just throwing it out there to get destroyed immediately and accomplish nothing.

~15/16 MQ-9 Reapers have been shot down inside Iran. Not jets but still combat(strike and reconnaissance) aircraft.

I just looked it up. Those are turboprop (slower) but have a high ceiling of 50k feet. So Iran did have something better than stingers left. Maybe they just got lucky this time.

I didn't downvote, but your post sounds like you're implying some kind of tomfoolery, deception, or other hidden reasons. There are very likely none, it just takes time to adapt to a specific enemy, probability slowly increases while you get more attempts, and then after some time (t) the first shootdown is "properly" successful. And note how this was preceded by that half-successful shootdown where the plane made an emergency landing. And they shot down drones.

You sound like they roll an antiaircraft cannon out of the hangar and immediately successfully down a plane. That's not how that works. The AA was probably there from the beginning, just not successful.

We don't know what downed it yet, so it's hard to say. Iran is hiding and rationing their offensive munitions, we know that, so it's not surprising when the number of drone and missile attacks spikes after weeks of bombing. That's part of the plan. But the ability to take down a US fighter jet is not something they are rationing- it's likely at the edge of their capabilities and they got lucky. If they could be knocking down more, they would be.

Because it obviously doesn't have the capability. Similar to how the US has no capability to "win" from the air only.

Maybe it was friendly fire but I did not see that in the news yet.

It's not entirely impossible that someone smuggled in some Chinese or Russian kit in the last month. It would certainly be an interesting development. I wouldn't be too surprised if there are some sympathetic people in the Pakistani military prone to misplacing things.