I'm not an "electronics" guy, but it seems to me that what you are measuring is the resistance through the spark plug, from the connector at the top to the electrode tip. You're essentially measuring the 'wiring' inside the ceramic insulator that takes the current to the elctrode. Who knows what's going on in there??? Sounds to me like they purposely build resistance in there to supress the 'noise.' It may not even be copper conductor inside there, although I suspect is copper taking the current in and out of the resistor.
It seems to me that what goes on inside the ceramic doesn't mean a thing as long is there is sufficient power generated from the coilpack, so the votage drop through the resistance inside the ceramic insulator doesn't prevent there from being enough juice to jump the gap, and there is plenty of that to spare. What matters is how the juice travels through the electrode tip and how attractive the "target" on the other side of the gap is, and how easily the juice flows through it to ground.
That copper has a lower resistance value than platinum is fact and indisputable.
What you seem to have proven is that one manufacturer's spark plug's resistance from connector to electrode is significantly higher than another. While an interesting fact, in a normally operating coilpack, it should have no effect on spark at all. The higher resistance may or may not be overkill for noise suppression, but that may not be a bad thing ...
Disclaimer: It's only 6:00 a.m., I just woke up, and the only thing I know about electricity is that A = VR, so you "electron heads" out there feel free to flame me if I've got it wrong. It will teach me once again not to post beyond my experience.....
'96 T-Bird LX 4.6L Alive & well & living in S. Florida
N/A: Renegade NPI heads/Comp Cams; OEM intake manifold; Bolt-ons
245 rwhp; 13.713 @ 99.35 (Commerce, GA - November 2003)
BLOWN: Renegade NPI heads; Renegade shortblock; Intercooled T-Trim; some other stuff
Pump Gas Numbers - 547 rwhp / 525 ft.lbs; Best Time - 11.388 @ 118.68 (Commerce, GA - November 2007)