I respect your point but I don't agree with you. I think style is something that comes to you, it's something that influences you. Personally I don't work at style at all, I draw the way that feel natural to me. When you see stuff you get blown away by, you take some of what you see in you and I believe that you do so without even knowing it. Sometimes you get influenced a lot sometimes you get influenced just a tiny bit. But everything gets mixed in the soup.
Fundamentals are something you work at, style is something that grows in you. You don't work it.
edit: also, the reason why people change their style is because the way they draw doesn't feel right to them, it doesn't feel natural. I've never had to work on style, I don't even bother to care about style. I draw what feels right.
(warning: wall of text ahead)
And I respect your point, but I don't think you've understood my point completely. I never said that style doesn't come to you, of course it does, and ofcourse you will be subconciously influenced by other work, I know I am and everyone else is. When you talk about working fundamentals you're aware you cannot avoid that you're at the same time influencing your style?
Because, if you work in a late 19th century academical style you most likely start with copying the outline of the object and then copy the shadow edges of the object. The fact that you do this instead of the renaisance method of working crosshatch on top of a volumetric line drawing allready will present you with a different outcome. Now if you take the cell shaded drawing and add in the midtones and shadows you're already changing the style again from an abstraction to an illusionistic way of drawing. When you know this you can say to yourself 'I'm only going to use the block in and transition to light and use a high saturated color in the shadows to increase the illusion of glowing skin'. This is a change of style yet in essence it's a purely technical decision. If you decide to paint in the old school fundamental way of glazing and scumbling in layer, or work in the new school fundamental way of painting alla primma you'll get a different look. If you decide that a particular project needs a more sinister look and feel you decide to use more elongated proportions of say 10 or 11 heads instead of 7-8 and make the eyes smaller, and use a brush and ink instead of pen to give everything a more raspier look. This is perfectly possible without having to 'force' yourself completely.
Ofcourse if you're into 1930's Disney stuff and decide you're going to draw a la Shirow you're going to have a hard time. But that's not my point. My point is that technique and style are not rivals but companions. Technique determines style and deciding on a style should result in a thinking and research process of how you can change you technique to get your desired results. The entire notion that style is some magical spiritual given that cannot be determined upon is just nonsense in my opinion. If you're working for Disney and are doing Aristocats and the next year have to work on Lilo and Stitch and cannot draw these different styled characters you have a big problem. The reason profesionals tell newbies to not focus on style is because it's entirely besides the question in their stage of development, they shouldn't be focusing on the 'what' but on the 'how'.
Personal style is something that grows, I'm not saying that everytime you sit down behind your wacom you force yourself to draw like artist X or artist y, ofcourse you do your own thing, and offcourse you'll be influenced subconciously by your favourite artists, as well by your own personality.
I guess it depends for a large part on your way of thinking. When I'm browsing the web and I see a certain piece of art I really like I often think 'oh hell yeah! everyone should draw like this!' and then the next great thing I see I'm like 'oh no no, everyone should be drawing like this!'. I like to analyze other artists work, and sometimes put a bunch of images I like together and see what they've got in common, is it their use of proportion, is it their way of lighting?' I used to enjoy allot of work, yet I didn't know WHY I liked it so much, but from observing and using the things I learned trough my fundamental studies I can see the differences and determine their way of working and thinking behind it, which if I like it enough can play around with myself to see where it gets me, and it's like you said, it gets added into the soup, it does grow, but I think that you can purposefully influence if if you're aware of what you're doing. That's also where the fundamentals come in.
The great thing about art is, once you reach a certain point in knowledge and ability it all ties toghether in a big whole, like a tree thagt branches out. And things that seemed seperate all of the sudden merge into one cosmic substance. And you can see the same principles in music, literature, math, graphics design, architecture, nature... there are a lot of 'rules' that apply to a pletora of fields. Style is not a purely aesthetic given, it contains everything from composition to storytelling to integration into the enviroment. Everything is relative to everything else, which I think is THE fundamental rule in art in general, and perhaps life even.

By the way, I'm not saying you're wrong or anything, just that maybe you're not seeying the complete picture yet. I know I'm not, I doubt I ever will.