Every so often a thread comes up and someone decries any plastic trim on an expensive guitar, as though plastic somehow makes the guitar appear cheap. Actually, the tradition of using a cream-colored material with wood parts in luthiery didn't start with plastic; it began with ivory.
Ivory was used as an inlay and trim material on mandolins, chittaras (note the similarity to the word "guitar" which derives from it), vihuelas and other stringed instruments that were guitar predecessors, going back to examples we have from at least the middle ages. Here are a few examples dating to the Renaissance:
As you can see, not only was the ivory used to decorate the fingerboard, headstock, and other parts, it was also used to conceal the joints of the instrument and highlight the shapes. The fact is that ivory, a material that doesn't have a wood grain, looks great next to (and contrasts very nicely with) wood, especially different types of wood, such as where the rosewood sides of a guitar meet, say, a spruce or cedar top. Thus guitars began to have a traditional look, with strips of ivory inlaid around the edges of guitars as a binding, often alternating with other materials, etc.
Ivory was also used as a material to inlay furniture, and to make things like pool balls. Sometime in the late 19th century, ivory began to become scarce, expensive, and difficult to obtain. In fact, the first type of plastic that was invented, celluloid, was originally used for pool balls for this very reason; balls made of ivory were impossible to find. Celluloid was a very effective material, though pool balls made of it did occasionally explode when struck together due to the chemicals used to make the plastic, and trigger wild west gun fights (this is true)!
In any event, luthiers began to use plastic to replace ivory as stocks of the stuff were depleted in the market. The plastic was created to look like ivory - hence, the cream color of bindings made from it, etc. If you want to know, "Why specifically cream-colored plastic?", there's your answer.
Wherever a luthier might have used ivory - such as on a rosette around the sound hole, a traditional place to include ivory rings - ivory colored plastic came into use.
It is easy to see how the pickups - that began to be stuck on in place of the sound hole on solid body guitars - would still retain a traditional look with trim rings reminiscent of the trim on sound holes. Since plastic had by this time already completely replaced ivory on even the finest guitars, it looked "right" as a pickup surround. And what looks "right" or normal to us is generally aesthetically pleasing.
I believe that our sense of aesthetic history, what looks "right" to us, has a lot to do with the actual history of the use of the materials. Anyway, I like the ivory colored plastic trim because it does look right to me.
As we all know, ivory importation simply ain't happening again because people are against slaughtering elephants for their tusks. So I'm good with the plastic rings; they preserve something of the materials tradition, at least in terms of look, texture, and color, while not endangering a species.
Interesting side note:
One of the vihuelas in the article I linked, made in the 1580s, was evidently still in use and modded around 100-120 years later; when instruments with shorter necks came into vogue, they simply cut down the neck on the thing.
But think about that - this instrument was so cherished, and probably so valuable, that it was being regularly played and appreciated as a musical instrument, not one or two years or decades after it was made, but centuries (!) after it was made, and no doubt thereafter until it finally wound up in a 20th century museum collection. That's really something, and it tells us a lot about our own disposable society. We have folks today who buy a guitar seemingly once a week, play it for a short time, and flip it for whatever reason. That's ok, and all, but I wonder if we wouldn't be better off spending some time with our instruments. As an example, it took me well over a month to begin to get to know and understand the capabilities of my SC58. I had a couple of friends suggest I should flip it, but I'm very glad I didn't, as it's become a huge part of what I do on guitar! And I'm still only scratching the surface of what it does. Same with other instruments.
I am thinking more and more that there is something important to humans about appreciating, even cherishing, what's in our hands. The satisfaction increases. There is closure in a certain way. There is personal history with something; maybe there's mojo. Probably just the crazed ideations of a 2000 year old man...yet these ideas seem to resonate with me.