Since you're an expert on connectors, perhaps you can fill us in on their manufacturing as well as how and why different metals are used in their construction.
Now, Myles, if I wasn't such a nice chap, I might think you were having a go at me ...
It's very straightforward. If the connection is a true gas tight connection, best done with the heaviest duty crimping tool you can muster, then I haven't got a problem with things. If it is a miserable RCA socket, which is widely recognised as an appalling example of bad engineering, then I'll run away and hide.
The big trouble is not which metal, but that the same or different metals are barely touching each other, at the microscopic level, at connection points.
Result: almost instant onset of corrosion, then diodic effects, and thermoelectric effects all doing a great job of injecting low level nasties, so in comes IMD and, finally, rough sounding tweeters.
Solutions: hardwire everything, silver pastes, contact cleaners, enhancers, on and on it goes. Pick your poison ...
Guess what? The USA (I think?) lost a $Xmillion jet, because the wiring harnesses, which used the very highest quality gold plated connectors, STILL developed a corrosion after about 6 months, I think it was, to the point that the electronics played up, and the plane went down. This was determined by an enquiry after the accident ...
Frank