We need to have realistic expectations though - air defense is an inherently asymmetric problem. The US broadly has the best air defense, but it's explicitly not focused on Russia or China, because it acknowledges that deterrence is the only plausible defense there.

While Iran isn't a superpower, they have hypersonic weapons that no system can intercept very reliably, and a sizeable assortment of ballistic missiles. Even if all other militaries joined forces, they probably couldn't intercept every single projectile coming out of Iran, at least not without depleting their interceptors to unacceptable levels.