yeah, of course phalanx never works. because of that, it is used by 19 nations. seems the majority of the worlds navies disagree with your USN sailors
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and note, I am not saying the 57 and 76mm guns cannot do CIWS. I am just saying that they are about as good, if not worse, then the systems that are actually designed to do that task, instead of systems adapted for it (this goes more for the 76mm then the bofors 57mm, which was in it's original form designed exactly for the task CIWS does now)
on stealth, you have a point, but if the effect of the CIWS mounting on RCS is that much, maybe you have gone a bit overboard with stealth. (to the level where the radar reflection of the wake of the ship shows exactly where the ship is, making that ship only stealthy when being slow) note how the LCS for example also use the less stealthy variant of the 57mm gun then the visby class uses.
and as far as I know, the wall of lead worked pretty damn good. also, goalkeepers hit, on average, with the first 2-5 bullets being fired, so a salvo of 10 can destroy any incoming target for certain...... not really an wall of lead (this counts more for the phalanx)
it's just not that simple when comparing CIWS and guns with each other as you think it is.