On the note of lacking Iranian IADS which has been brought up repeatedly over the last couple days:
I think it's important to keep in mind that a proper, large scale, integrated air defense network covering long, medium and short range systems was never in the cards for Iran. A single modern SAM battery is already terribly expensive, and Iran isn't particularly well off. We're talking about a country that relies on decades old imports and their admittedly more capable indigenous drone and missile industry to support their military. Not only are modern SAM batteries extremely costly, there is no chance to cover the entirety of the vast Iranian lands reliably. And on top of that, the amount of SAM systems required to successfully deter the IDAF and USAF would be astronomical, as these are two Air Forces which pride themselves with decades to SEAD expertise and deploying the tailormade tools for the job.
In short, it would have been largely a waste of money and resources, because an IADS network would have bankrupted Iran, as they would have needed a record breaking amount of launchers and radars in order to effectively repell the Americans and Israelis. Which, to be honest, would have still overwhelmed these SAM systems eventually.
Instead Iran choose the other side of this equation. Cheap and numerous drones and missiles, launched from mobile, inconspicuous or hardened locations, overwhelming and out-trading US and Israeli anti-air systems with an economically favorable ratio. And this instance follows the precedent set by Russia in Ukraine that the whole spectrum of drones and missiles will overwhelm even highly concentrated air defense networks meant to protect high priority assets. This should put everyone on notice who believes that hiding behind layers and layers of air and missile defense will protect them, it won't. When the opponent is able to iterate, manufacture and deploy cheap drones and cost effective missiles, the odds of your IADS getting overwhelmed and ultimately dismantled increase dramatically.
SEAD and DEAD don't have to be conducted through combat aviation, if you can muster the necessary amount of munitions to drown your adversaries defences in them, then it's the more cost effective solution in the grand scheme of things.
And while this means that the adversary can semi-freely operate in your air space (Iran still has other means of engaging opposing aircraft, especially more vulnerable drones), if you are prepared for this scenario and continue to be able to harass and inflict heavy damage on your opponent, you will push them further and further out, which will hurt sortie generation and will give you breathing room. Not to mention the damages to material, personelle and infrastructure you can cause in the mean time.
So no, I don't think it would have been smart of Iran to invest in vanity projects which would have left them defenseless after a few days. Be it sinking huge sums into IADS, massively modernizing the IRIAF or their Navy. No matter how many of their limited resources they would have spent, they would have always been at an disadvantage regardless. So it necessitated an asymmetrical approach, which we're seeing now in action. Not to mention that it would have still been iffy if Russia or China sold them anything useful in prior years, despite big rhetoric, both have historically been averse to circumvent western sanctions openly on other countries. To their own detriment, quite frankly (both believing with the US could be reasoned and that international rules and the likes mean something) .