I have a few questions for you if you don't mind.
1) Do you think Syria has shot down literally 0 PGMs?
2) If no, have they shown any fragments?
3) If the Syrian IADS is such a total failure why has neither Russia or Iran delivered more capable systems? Russia might have some agreements with Israel about this but Iran certainly doesn't. And they're the ones getting hit.
4) Is there any evidence of Israeli strikes from inside Syrian airspace post shoot down?
On a side note, Syria isn't the only route to Iraq. During the strike on Osirak iirc didn't Israel go through Saudi airspace? Given the recent warming up between Saudi Arabia and Israel (especially their cooperation vis-a-vis Yemen) isn't it possible, or even likely, that the Saudis would be willing to allow Israeli warplanes through?
I'm not convinced that Russia sold Syria the systems. They're S-300PM systems, a variant not ever exported because it's a domestic variant specifically. It's likely closest export variant is the PMU1. They're operating Russian IFFs, they came straight from a Russian SAM regiment that was re-armed with S-400s, and they're reportedly operating under Russian command. They also haven't participated in the current scuffles at all as far as I can tell. I suspect they provide extra launch tubes for the Russian IADS along the Syrian coast, with some Syrian staff on site. Given just how few TELs the S-400s at Khmeimeem have, this would make sense.
EDIT: Consider that in Russian S-400 regiment, often they don't replace the TELs when they re-arm. I.e. the TELs are completely (or nearly so) interoperable between the S-300P and the S-400.
1)Statistically, with several thousand munitions dropped on Syria, it would be illogical to think 0 munitions were shot down. However, typical Israeli munitions are low RCS, especially the SPICE and SDB bombs, and even the Delilah.
Syrian air defenses are geared towards very high RCS targets like manned fighters and large aircraft.
Only few in-service systems are capable, like the Pantsir. Which leads me to the next point.
2)Exactly - they haven't shown any fragments from allegedly downed missiles. Pantsirs are confirmed beyond doubt to have been operationally used. However, not a single fragment of a downed Israeli missile was shown to the public. And as we know, the Syrian media is thrilled to show such fragments every chance they get.
Israeli artillery uses semi-reusable catapult launched drones. They're cheap, somewhat dispensable, and take some beating every time they land for reuse. So the IDF loses them at a fairly high rate, even outside combat. Occasionally they malfunction over enemy territory and land in Syria or Lebanon or even Gaza.
Syrian media gladly showcased these every time they found one.
3)Russia - likely not because of agreements, but because they understand that Syria does not have the physical means or expertise to use them properly, so their systems would get destroyed at a disproportionately high rate.
For example, the only reason why in 1973 Egypt inflicted so many losses to the IAF with SAMs was because Egypt had an effective air force.
Letting only SAMs engage with aircraft is like ordering catapult operators to face a cavalry charge.
Iran - they tried, but there were reports of Israeli strikes against components of Iranian systems. They cannot transport them whole, lest they'll be spotted.
But regardless, Israel's intelligence grip on Iran is ridiculously tight. They also have their own financial troubles. Losing highly expensive equipment every other week is taking a toll on Iran's resources and morale alike. After operation House of Cards in 2019, remaining Iranian forces have largely withdrawn from southern Syria.
4)Direct evidence? No. But we do know SDB or SPICE bombs (both glide bombs with similar characteristics) are the go-to weapon for the IAF in Syria.
To think Israel would always be firing from within Israeli territory, it would require Israeli aircraft to fly at an altitude of 5km in circles, for 17 minutes for a Delilah missile to hit at max range. That is by all means a terrible strategy, especially considering it allows Syrian S-200 to threaten Israeli aircraft within Israeli airspace.
SDBs and SPICE have approximately 100km range from high altitude (can fly low then make a short climb and release, then descend and return).
Considering that much of the footage of Israeli strikes in Syria shows exceptionally large explosions, we can assume the longest range weapon known in its arsenal, the 20kg warhead Delilah, is not so frequently used as thought.
Googling "ISI Syria" will show plenty of results of large craters or large destroyed targets very deep inside Syria.
There is simply no SAM in Syrian inventory that can threaten Israeli aircraft on their way to a destination. Only point defenses that can show some capability on the destination itself, where they'll be dealing with low RCS munitions only.
The Osirak reactor is not the best example. Neither Jordan nor Saudi Arabia were friendly with Israel. That was 13 years before Jordan accepted a peace treaty with Israel.
Even today, Saudi Arabia does not allow Israeli planes to fly over its territory. And with the use of advanced radars, Israel cannot really conceal such a flight route, and would rather not risk the diplomatic incident especially when such strikes are routine.
Even then, the targets were very deep in Iraq as well, and the need for concealment likely dictated short range munitions to be used.
Furthermore, Israel and Syria were warring parties in 1981 but they maintained a ceasefire. Israel would not risk breaking that ceasefire, especially considering Syria had an extremely potent air defense force, air force, and surveillance capabilities back then that could jeopardize the entire operation.
Today, Israel and Syria no longer have a ceasefire agreement in effect (frozen indefinitely), so the diplomatic obstacle to using Syrian territory is lifted.
What would be the obstacle for Russia to just get more launchers into Khmeimim or a remote storage facility? Surely any arrangement would be better than the PR disaster the S-300 system suffered due to the sale to Syria.