Re: The Kelvin's uniforms
I think it is quite likely that the gold details didn't look good or stand out enough on-screen with the new yellow/gold/avocado command uniforms.
Besides, the Starfleet/Enterprise chevron was small and silver
during The Cage, so a color change isn't a big deal.
"STAR TREK is... Action - Adventure - Science Fiction."
-- Gene Roddenberry, 1964, top of the first page of his original pitch and outline for Star Trek