I think your disagreement is my fault - I could have stated my thought more clearly. Let me see if I can remedy that: Let's say you have two riflemen, both shooting under optics, and one has substantial experience shooting irons and the other none. It occurs to me that, everything else being equal, the former would have a better - admittedly very slight, but still better - subconscious "feel" for the shot.
Terry is completely correct that an optic helps the shooter see better, not hit better. That is a crucial point that, unfortunately, is lost on many riflemen, especially the hunters with whom I regularly come in contact, many of whom seem to think that one's ability to competently hit a target increases in direct proportion to the cost of the scope he's using (e.g.: "I want to hit a more distant target, so I bought a higher-magnification scope.")
Certainly, the pure-scope guys enjoy the benefits of substantial practice, and the absorbed information that goes with it. This is the same zen, as SatCong so aptly described it, which I would argue is possible only through substantial experience shooting rifles, sighted with irons OR optics, and absorbing both the observed and subconsciously imparted effects of the bullet on its way to the target - andy's point.
The difference I am suggesting - and again with two well-practiced riflemen it would be admittedly slight - is that the information the iron-sight guys have picked up over time might be more detailed and of broader scope. Why? Because over time it has been received directly from the reactive indicator instead of through the scope, and without the scope to filter the incoming data, the entirety of the situation surrouding each piece of reactive indicia is received.
Clear as mud?
Let's approach it from another direction. Let say you have the same two experienced riflemen, all things equal as before, one experienced with both irons and optics and the other with optics only. Would I be incorrect in assuming that in a heads-up contest (remember, this is a question in a vaccuum - no external factors to contend with - sorta like the rifle version of the IROC races?

) that the shooter with the additional iron-sight experience might have a slight edge? Or perhaps even more precisely, have a slight edge IF an unusual set of shot factors presented itself?
Regards,
Jon