To All Cable Deniers, 1 Very Simple Question.

"Unfortunately no one has asked if the plug is 30% copper, then what is the other 70% because that’d be a VERY good question."

No mystery whatsoever.  My response early in this thread about outlet metals also applies to plugs.  Most plugs are made from lower copper content alloys of copper in order to enhance strength and corrosion resistance.  Common alloys used are Brass, Bronze, and Beryllium-copper.  The other metals in these alloys typically consist of zinc, tin, nickel, or aluminum.  These alloys are all conductive, just less conductive than pure copper, and have been used in power connectors for many years with the lower conductivity being an inconsequential trade-off in order to gain strength and corrosion resistance.

I believe I fit somewhere in the middle ground with respect to cables.  Being married to an Ivy PhD Economist, we believe in marginal cost / marginal gain.

Only you can determine when the cost to get that last percentage of audio gain (and I do not mean volume,LOL). Is a bridge too far.

Good cables make a difference until they don’t.

Can the OP hear the difference between the copper content in the plug pins?  Yea or nay.

Can the OP hear the fuse holders in his presumably very expensive (because you get what you pay for!), elevated high-end audio gear? Those are made of garden-variety steel (to snap security onto the fuse).

What about the inexpensive ribbon cables and IDC connectors, same as those in lowly PCs, can he hear them?

Or all the discrete components inside said audio gear - the resistors, caps, semiconductors - the vast, vast majority of which have ferrous alloy leads, such that you can pick up any transistor or diode with a small magnet. O the horror! Surely OP can hear that, can he?

It’s always hilarious to watch self-appointed Audiophiles pontificate about infinitesimal differences in things they can see, such as wall receptacles or cable elevators, while being completely oblivious of the far worse transgressions that lurk inside their gear. Out of sight, out of Golden Ear?

To jump in re the Ohno casting of wire, it’s not the resistance variation that matters, it’s the effect of grain boundaries on impedance that matters, as it varies with frequency and affects phasing. Our ears are exquisitely sensitive to phasing with frequency.