I just like to stick to the meat and potatoes logic: Style is just the way an individual, both the artist and audience, perceives it's creation. Several things could contribute to why their style looks that way, but do humans REALLY know why their pieces come out so differently than others? It always amazes me how different everybodies perception of something is. You can dress up 40 kids in the same outfit, and cut their hair the same way, but leave them all to draw the same object in a room, and you will most definitely see a stark difference in each of them. Almost a perceptual fingerprint of our mentallity, that we probably still aren't aware of. That would be crazy, though, to get to the point where authorities would be able to identify you by your art. They already do it with signatures.(*light blinks on for more brainstorming on current/ongoing plot twist of fictional comic/story*)
I still believe in the old practice habits that one should always try and perfect his skill no matter his excuse of what level he is at. There's always room for improvement, and style is NEVER a limit. Sure style may be flawed to one set of eyes, but to others, its new and refreshing. "one man's trash is another's gold."
edit: " Warning - while you were typing a new reply has been posted. You may wish to review your post.": Helm, you quick bastard...