For the sake of argument, why wouldn't this also extend to my written 'voice'?

(I'm talking philosophically by the way, not legally)

For someone like Cormac McCarthy, whose sparse punctuation, biblical cadences, and apocalyptic imagery create an unmistakable "voice," the argument seems strong. His style is as identifiable as vocal timbre e.g. readers recognize McCarthy prose instantly, just as they'd recognize his speaking voice.