I almost never think anything in business is a zero-sum game, least of all intangible things like branding or aesthetics. But some part of me thinks that a lot of last year's success of the Livestrong brand (and those ubiquitous bracelets) must have come at the expense of the sales of NYPD and FDNY gear. There may only be room in the public consciousness for one "public empathy" brand, and if so, that would also explain why so many of the other attempts at making colored bracelets haven't succeeded.
Also, given that the Livestrong yellow color took off last year at the same time that the iPod was ascending to its status as a cultural icon, how come nobody at Apple wanted to pair up and make a bright yellow iPod? Half the iPods available today come in black, so the white color's already not as pure a representation of iPods anyway, and safety yellow is probably the only color that's as high-impact as white.
There's also a lot of missed opportunities for third parties: one thing that amazes me about iPod headphones is that the cheap knockoff audio brands that I see at airports (I'm looking at you, Coby...) still aren't selling generic white earbuds with their low-end products. People who are deciding between two identical $30 CD players at an airport would probably choose the one with the white headphones if it means they might get mistaken for one of the cool kids. And losing the monopoly on white headphones (which still doesn't seem to have happened, despite the PSP using white phones) would actually force Apple to innovate on their iPod marketing, which has pretty much stagnated since they switched from first-person testimonials in front of a white screen to dancing silhouettes.
There's a real challenge there... what do you do with the white headphones in ads if most iPods being sold don't have them? Cordless headphones, black earbuds, the entire iconography of iPod ads could be obsolete in a year if Apple's product team wanted to make that happen. And they'll need to be ready for the inevitable backlash, once the iPod has truly reached its saturation point (meaning the people who are on their second or third iPods start to get upgrade fatigue) and people are hungry for a new visual to go along with the player.
Maybe they could find a way to make owning an iPod seem like it'll cure cancer.