It has been known for some time that gun-type CIWS like the Phalanx and Goalkeeper are obsolete against modern cruise missile designs. Another dirty secret is their efficacy against saturation attacks from modern supersonic cruise missiles (by modern I mean the Oniks/Yakhont not the Moskit/Sunburn) coming at different altitude vectors. Let’s just say that a military confrontation between major/regional players would be quite different from an Iraq/Bosnian/Afghanistan campaign. Many lives would be lost from what some on FR call useless equipment.
I was referring to the actual efficacy of the main anti-missile defence systems, that is, the Standard Missile plus ESSM mix. The gun-type R2D2 systems have been known to be ineffective for some time, but there are concerns about the efficacy of mid and short range missile systems against a saturation attack of high speed maneuvering missiles. It was always the case even back in the days of the Sunburn but modern missiles like the Yakhont and the Klub make it greater. Defensive missiles like the modern variants of the Standard have also become much more effective, and of course the ESSM and rolling airframe missile make the short game much better, but a swarm of incoming Yakhonts would almost guarantee a mission kill at least. Only one needs to get through, and the kinetic speed alone would be sufficient to accomplish a mission kill - even if the warhead did not detonate. This is why active phased array radars - in essence AESAs - and far faster and more agile anti-missile missiles, are imperative.