Hi Fried Chicken Boy,
trust me. I know what I´m doing and saying. I have been working as a design engineer for electronic systems for the last quarter of a century. Whenever you want to transfer low-level signals between contacts (and microphone and consumer line levels fall into that category), you either use thick gold plating or you have to "wet" the contact with a dc current in the mA range to break through a tiny oxide film that forms on the two contact areas if the contact material is something else. Signal relays for low level signals mostly use AgPd contacts with gold plating because massive gold contacts would be too expensive. Silver alone tarnishes, not to talk about the effects of sulphur on silver (this gives a nice, black insulating layer - anyone who has some Texas Instruments TTL chips from the seventies in his junk box knows that). Cost drives the replacement of gold in contact applications - for most applications there is a suitable substitute, but a well made gold plating (and I bet Neutrik knows how to do it) still beats all substitutes when it comes to reliability in low-level signal switching.
My Neutrik 3.5mm plug is used in outdoor applications, where it gets wet or dirty. I clean it regularly with denaturated alcohol and wipe it clean with a paper handkerchief before plugging it in. From time to time I treat it with a special cleaner for gold plated contacts (Kontakt Chemie "Gold 2000"). After a year of intensive use, it still looks like new.
My experience in the last decades concerning connectors has been this: buy well-made connectors from reputable manufacturers. Saving on connectors (and cables) increase the probability that you lose a valuable recording, maybe one that cannot be repeated. Been there, done that.
Greetings,
Rainer