I'm not expert on weapons, so this is just a layman consulting youtube for knowledge and this guy says penetrating Fordow, in short, will require at the very least 1/3rd of America's bunker buster arsenal, which they may not be willing to expend.
So now that we're a week in I like many eithers jumped to some far fetched conclusions when this all brokeout and of course being just a guy who casually follows this stuff rather than a professional, most of my conclusions turned out to be wrong.
This hasn't become a quagmire yet, so we can gleen that Israel still has two core objectives so far. Destruction of Iran's nuclear program and regime change. With respect to the former, my main reference is the aforementioned video which says that even with US involvement, it'll hardly be a walk in the park. The only real way to knock out the nuclear sites for good would be a ground invasion or for Sayeret Matkal to basically be flown to their objective 1000 km deep into Iranian territory, fighting through whatever security they encounter which will at the very least be brigade sized, blast through multiple layers of reinforced doors, all with very minimal hope of extraction. Yeah if Rambo was given this mission in part 2 he would've said, "Nah fam, hard labor life for me!"
As for regime change, I know reddit is not a great reference point for anything. But an Iranian dissident has been spreading word on multiple subs sounding the alarm that the strikes are actually radicalizing large sections of the Iran's population, even for those typically anti-regime. Considering that the hardest Iranian dissidents are the more educated English speaking types who are either diaspora or have ties to the diaspora, if even they are expressing this sentiment it probably stands to reason the real public sentiment in Iran is much more extreme. Imo, much like how Russia misjudged the common culture component when fighting the Ukrainians, Israelis and Americans alike took the polls ranking public discontent in Iran at 80% too much at face value as well as the tendency to romanticize those images of life in pre-revolutionary Iran in conjunction with the constant framing of Iran as a successor state to the pre-Islamic Persian Empires. So essentially, taking up the objective of regime change with an orientalist image of Iran being this civilizational state held hostage by a foreign religion and welcoming Israeli as well as American bombs as a form of twisted liberation.
First off, previous mass protests in Iran have always been suppressed not just because of the hardline tactics of the regime, but because no opposition has ever existed in modern Iran to begin with. Seriously, as pathetic as the Venezuelan "coup" was, anyone following the news even casually could at least point to Juan Guaido as an opposition figure, where is Iran's equivalent? Most important of all, yes conditions in Iran have not been great and plenty of people hate the regime, yes there are so called "Persian nationalists." But Iran is only 60% Persian and hosts numerous other ethnic groups. Nobody, even someone's whose born and raised there can possibly know all the cultural makeup of these groups, what they want, and what their idea of "Iranic" is, although it wouldn't be too far fetched to say to some extent as abhorrent as the IRI can be at times, it does provide some semblance of national unity.
But above all, whatever liberation a nation goes through, it has to be homegrown. Israel from the beginning posited itself as Iran's outside liberator. However different Iranians may be and their feelings about religion, they are a righteous people and I'm sure they would have so have choice words for what exactly a nation that treats people lining up for food aid as point black target practice can do with its so called, "liberation."
So in short, yes Iran has sustained heavy casualties. But two objectives set out by the Israelis and neither for the moment seem all that accomplishable. So the ball's still in their court with respect to how long do they want to keep this up.